We're pausing our live coverage now, as the search for a missing child continues in Brighton.
Police are looking in an extensive outdoor area for the infant and say the newborn's parents, Constance Marten and Mark Gordon, have been further arrested on suspicion of gross negligence manslaughter.
Today's page was written by Laura Gozzi, Sam Hancock and Emily McGarvey. It was edited by Marita Moloney and Tom Spender.
You can continue to follow the latest updates here.
WATCH: Our focus is on finding the baby, police say
Video content
Video caption: Police say their focus is on finding the missing babyPolice say their focus is on finding the missing baby
Earlier, Chief Supt James Collis from Sussex Police and Det Supt Lewis Basford from the Met spoke to the media in Brighton.
They said they were searching a "vast amount of land" for the missing child, and asked the public to be vigilant.
Post update
.Copyright: .
Key police updates on the search for missing baby
BBCCopyright: BBC
We've just heard an update from the Metropolitan and Sussex Police forces in Brighton about their search for a missing baby.
Here's what we learned:
Constance Marten and Mark Gordon have now been further arrested on suspicion of gross negligence manslaughter
The child still hasn't been found, but the harsh weather conditions mean the risk to the newborn's welfare is "so great" that police are considering the possibility that the baby has "come to harm"
The couple have given police no information as to the gender of the child
Marten and Gordon had clearly spent a "considerable amount of time outdoors" when they were found following a tip-off from a member of the public on Monday night, police said
More than 200 officers continue to search a "vast outdoor area" in Sussex
Pair had substantial amount of cash on them
Asked if someone had been taking care of the baby on the couple's behalf, the detectives say they have to keep an open mind and that's why they offered a £10,000 reward, which is still being offered.
Police say the couple had a substantial amount of cash on them.
The police end the press conference by saying they will continue to search diligently search for the baby.
Couple had clearly been living outside when arrested
Police are asked about the state and condition of the couple when they were arrested.
They say it was clear quite quickly that Constance Marten and Mark Gordon had spent a "considerable amount of time outdoors".
Pushed on whether camp equipment was found, police repeat that they're happy to confirm that the couple have been living in "vast outdoor" areas that can be found in Sussex.
Couple arrested after being seen using cash machine
Asked for more detail about how the member of the public reported seeing the couple, the detective says that "it was a diligent member of the public" who observed them using a cash machine and then entering a shop and called 999.
Six minutes later, police arrived.
Detectives searching a large area of land
Detectives are sharing more details about the focus of the search.
They say they believe the couple were in open areas but they say "it's a vast amount of land" that includes outbuildings.
Police are looking at a corridor of seven miles by 13 miles, so 91 square miles are to be searched.
Couple moved across country very quickly - police
Police are asked what brought the couple to Brighton.
The Met's Lewis Basford says the investigation has shown police how quickly the couple had moved across the country since 5 January.
They went from Manchester to Liverpool to Essex to London and then to Sussex, he says, as has been reported.
No information on baby's gender yet
BBCCopyright: BBC
Asked if the couple are "cooperating" and giving more information on the newborn, Det Supt Basford says there is still "no information" on the gender of the baby.
He wouldn't be drawn on a timeframe for finding the child, but does says that due to the cold, "we have to remain open to the fact this may not end the way we would want" as the impact of cold weather would have endangered the child.
However, he says police remain hopeful.
'We have to consider possibility that baby has come to harm'
The detectives are taking questions from reporters now.
Det Supt Basford is asked for more details on the suspicion of gross negligence manslaughter the couple have further been arrested under.
He says "we feel the risk is getting so great we now have to consider the possibility that the baby has now come to harm".
Asked if the couple has admitted to that, he says the interview process is continuing.
"We still remain focused on an open land search to find the baby safe and well."
Police to remain in local area for some time
Chief Supt James Collis, of Sussex Police, is now talking. He says people in the area can expect an "increased police presence" going forward.
He adds this may cause disruption to locals, but it's necessary for the search to continue.
Collins thanks the local community for their "help so far", saying officers "will be here for some time".
Moving forward, he says people can help by being vigilant.
Police thank member of public
Officers thank the person who made the call which led to the couple's arrest in Brighton last night.
They were arrested within a few minutes of the phone call being made, they say.
Baby still missing, police say
The Met's Lewis Basford is still speaking. He says the couple's baby hasn't been found yet but police remain committed to searching.
Some 200 officers are in the process of looking, he says, with helicopters and drones helping from above.
BreakingCouple arrested on suspicion of gross negligence manslaughter
Police say they are continuing the search for the baby.
The parents were initially arrested for child neglect and have now been further arrested on suspicion of gross negligence manslaughter, Detective Superintendent Lewis Basford says.
BBCCopyright: BBC
Police press conference starting now
The police are beginning a press conference with updates on the massive search that is under way for a missing baby after a couple, Constance Marten and Mark Gordon, were found and arrested in Brighton.
Chief Supt James Collis from Sussex Police and Det Supt Lewis Basford from the Met Police will provide updates.
We've been having problems with the live stream from the police news conference. We will bring you updates here but apologise for the inconvenience.
Marten's father speaks of his relief and alarm
Constance Marten's father Napier Marten has told the Independent newspaper of his "relief" that his daughter had been found, although he did say it was "very alarming" that her baby remains missing.
Marten also said that it would have been "far better" if she and Gordon had handed themselves in earlier.
"For whatever reasons she and her partner went on the run, the consequences of their actions have increased many fold," he said.
He added that "when the time comes, I am longing to see Constance to reassure her that, whatever the weather, I love her dearly and will support her as best I can through the difficult weeks and months here on in."
No evidence couple gave baby to anyone - police
Earlier today Det Supt Lewis Basford from the Metropolitan Police told reporters that the police's "main line of hypothesis" was that Marten and Gordon were "in control and custody of the baby" and that "at no point have we seen, in that short period of CCTV... that they allowed others to have that baby".
The baby appears to have been "concealed within the coat lining of Constance or in the buggy for the short period they had it".
Basford said officers that while there was no sign the couple had given the baby to anybody else, police "could not rule out" that Marten and Gordon had found someone "like-minded or who does not conform or appreciate the establishment" and used the money they had for "safe lodging".
However, Basford also added that after the arrests, this line of inquiry did not become "as significant".
Police flood to quiet residential area in Brighton
Nick Johnson
Reporting from Brighton
BBCCopyright: BBC
This is a very quiet, very residential area on
the northern edge of Brighton.
Police
cars line the northern tip of Stanmer Villas - sandwiched between allotments
and a golf course. It’s in these undulating wooded areas where officers are
focusing their search.
Residents
in the houses facing the allotments have been hanging over their balconies -
keen to be abreast of any significant developments.
The
couple were spotted near a convenience store a short walk from here last
night.
Residents
near that row of shops say despite a circling police helicopter during the
night, they heard nothing of the arrest until switching on the news
this morning.
WATCH: Police search allotments on Sussex Downs
Hundreds of officers have been seen scouring an allotment and golf course on the Sussex Downs in Brighton, in an "urgent search" involving helicopters, drones and police dogs.
In a direct appeal to the public, police said the search was "now all about that baby".
Police cars were seen lining the northern tip of Stanmer Villas, sandwiched between Hollingbury Golf Course and Roedale Valley Allotments, where officers are focusing their search.
Video content
Video caption: Police search allotments for baby as Constance Marten and Mark Gordon arrestedPolice search allotments for baby as Constance Marten and Mark Gordon arrested
Live Reporting
Edited by Marita Moloney
All times stated are UK
Video caption: Police say their focus is on finding the missing babyPolice say their focus is on finding the missing baby 
.Copyright: . 
BBCCopyright: BBC -
Constance Marten and Mark Gordon have now been further arrested on suspicion of gross negligence manslaughter
-
The child still hasn't been found, but the harsh weather conditions mean the risk to the newborn's welfare is "so great" that police are considering the possibility that the baby has "come to harm"
-
The couple have given police no information as to the gender of the child
-
Marten and Gordon had clearly spent a "considerable amount of time outdoors" when they were found following a tip-off from a member of the public on Monday night, police said
-
More than 200 officers continue to search a "vast outdoor area" in Sussex
BBCCopyright: BBC 
BBCCopyright: BBC 
BBCCopyright: BBC Video caption: Police search allotments for baby as Constance Marten and Mark Gordon arrestedPolice search allotments for baby as Constance Marten and Mark Gordon arrested
Latest PostThanks for joining us
We're pausing our live coverage now, as the search for a missing child continues in Brighton.
Police are looking in an extensive outdoor area for the infant and say the newborn's parents, Constance Marten and Mark Gordon, have been further arrested on suspicion of gross negligence manslaughter.
Today's page was written by Laura Gozzi, Sam Hancock and Emily McGarvey. It was edited by Marita Moloney and Tom Spender.
You can continue to follow the latest updates here.
WATCH: Our focus is on finding the baby, police say
Video content
Earlier, Chief Supt James Collis from Sussex Police and Det Supt Lewis Basford from the Met spoke to the media in Brighton.
They said they were searching a "vast amount of land" for the missing child, and asked the public to be vigilant.
Post update
Key police updates on the search for missing baby
We've just heard an update from the Metropolitan and Sussex Police forces in Brighton about their search for a missing baby.
Here's what we learned:
Pair had substantial amount of cash on them
Asked if someone had been taking care of the baby on the couple's behalf, the detectives say they have to keep an open mind and that's why they offered a £10,000 reward, which is still being offered.
Police say the couple had a substantial amount of cash on them.
The police end the press conference by saying they will continue to search diligently search for the baby.
Couple had clearly been living outside when arrested
Police are asked about the state and condition of the couple when they were arrested.
They say it was clear quite quickly that Constance Marten and Mark Gordon had spent a "considerable amount of time outdoors".
Pushed on whether camp equipment was found, police repeat that they're happy to confirm that the couple have been living in "vast outdoor" areas that can be found in Sussex.
Couple arrested after being seen using cash machine
Asked for more detail about how the member of the public reported seeing the couple, the detective says that "it was a diligent member of the public" who observed them using a cash machine and then entering a shop and called 999.
Six minutes later, police arrived.
Detectives searching a large area of land
Detectives are sharing more details about the focus of the search.
They say they believe the couple were in open areas but they say "it's a vast amount of land" that includes outbuildings.
Police are looking at a corridor of seven miles by 13 miles, so 91 square miles are to be searched.
Couple moved across country very quickly - police
Police are asked what brought the couple to Brighton.
The Met's Lewis Basford says the investigation has shown police how quickly the couple had moved across the country since 5 January.
They went from Manchester to Liverpool to Essex to London and then to Sussex, he says, as has been reported.
No information on baby's gender yet
Asked if the couple are "cooperating" and giving more information on the newborn, Det Supt Basford says there is still "no information" on the gender of the baby.
He wouldn't be drawn on a timeframe for finding the child, but does says that due to the cold, "we have to remain open to the fact this may not end the way we would want" as the impact of cold weather would have endangered the child.
However, he says police remain hopeful.
'We have to consider possibility that baby has come to harm'
The detectives are taking questions from reporters now.
Det Supt Basford is asked for more details on the suspicion of gross negligence manslaughter the couple have further been arrested under.
He says "we feel the risk is getting so great we now have to consider the possibility that the baby has now come to harm".
Asked if the couple has admitted to that, he says the interview process is continuing.
"We still remain focused on an open land search to find the baby safe and well."
Police to remain in local area for some time
Chief Supt James Collis, of Sussex Police, is now talking. He says people in the area can expect an "increased police presence" going forward.
He adds this may cause disruption to locals, but it's necessary for the search to continue.
Collins thanks the local community for their "help so far", saying officers "will be here for some time".
Moving forward, he says people can help by being vigilant.
Police thank member of public
Officers thank the person who made the call which led to the couple's arrest in Brighton last night.
They were arrested within a few minutes of the phone call being made, they say.
Baby still missing, police say
The Met's Lewis Basford is still speaking. He says the couple's baby hasn't been found yet but police remain committed to searching.
Some 200 officers are in the process of looking, he says, with helicopters and drones helping from above.
BreakingCouple arrested on suspicion of gross negligence manslaughter
Police say they are continuing the search for the baby.
The parents were initially arrested for child neglect and have now been further arrested on suspicion of gross negligence manslaughter, Detective Superintendent Lewis Basford says.
Police press conference starting now
The police are beginning a press conference with updates on the massive search that is under way for a missing baby after a couple, Constance Marten and Mark Gordon, were found and arrested in Brighton.
Chief Supt James Collis from Sussex Police and Det Supt Lewis Basford from the Met Police will provide updates.
We've been having problems with the live stream from the police news conference. We will bring you updates here but apologise for the inconvenience.
Marten's father speaks of his relief and alarm
Constance Marten's father Napier Marten has told the Independent newspaper of his "relief" that his daughter had been found, although he did say it was "very alarming" that her baby remains missing.
Marten also said that it would have been "far better" if she and Gordon had handed themselves in earlier.
"For whatever reasons she and her partner went on the run, the consequences of their actions have increased many fold," he said.
He added that "when the time comes, I am longing to see Constance to reassure her that, whatever the weather, I love her dearly and will support her as best I can through the difficult weeks and months here on in."
No evidence couple gave baby to anyone - police
Earlier today Det Supt Lewis Basford from the Metropolitan Police told reporters that the police's "main line of hypothesis" was that Marten and Gordon were "in control and custody of the baby" and that "at no point have we seen, in that short period of CCTV... that they allowed others to have that baby".
The baby appears to have been "concealed within the coat lining of Constance or in the buggy for the short period they had it".
Basford said officers that while there was no sign the couple had given the baby to anybody else, police "could not rule out" that Marten and Gordon had found someone "like-minded or who does not conform or appreciate the establishment" and used the money they had for "safe lodging".
However, Basford also added that after the arrests, this line of inquiry did not become "as significant".
Police flood to quiet residential area in Brighton
Nick Johnson
Reporting from Brighton
This is a very quiet, very residential area on the northern edge of Brighton.
Police cars line the northern tip of Stanmer Villas - sandwiched between allotments and a golf course. It’s in these undulating wooded areas where officers are focusing their search.
Residents in the houses facing the allotments have been hanging over their balconies - keen to be abreast of any significant developments.
The couple were spotted near a convenience store a short walk from here last night.
Residents near that row of shops say despite a circling police helicopter during the night, they heard nothing of the arrest until switching on the news this morning.
WATCH: Police search allotments on Sussex Downs
Hundreds of officers have been seen scouring an allotment and golf course on the Sussex Downs in Brighton, in an "urgent search" involving helicopters, drones and police dogs.
In a direct appeal to the public, police said the search was "now all about that baby".
Police cars were seen lining the northern tip of Stanmer Villas, sandwiched between Hollingbury Golf Course and Roedale Valley Allotments, where officers are focusing their search.
Video content