• The terror threat level has been reduced from "critical" to "severe"

• A second suspect was arrested in Hounslow, west London on Saturday at 11.50pm
• Police are searching a home in nearby Stanwell, Surrey in connection with that arrest
• A search is also taking place at a property in Sunbury-on-Thames where it is believed an 18-year old suspect lives. He was arrested in Dover on Saturday morning
• Of the 30 people injured, one is still being treated in hospital

A property is being searched in Stanwell in connection with the arrest of a 21-year-old man in nearby Hounslow yesterday.

Image source, PA

Image source, PA

Assistant commissioner Mark Rowley says that investigators "are getting a greater understanding of the preparation of the device" used in Friday's attack.

Two house searches are continuing - both in Surrey - following the arrests of an 18-year old man in Kent and a 21-year old male in Hounslow on Saturday.

Mr Rowley said: "The high pace and rapid progress of this investigation is continuing."

Assistant commissioner Mark Rowley says that although the threat level to the UK from international terrorism has been reduced from critical "there is still a severe threat level".

He said: "If you see something you are worried about or know somebody you are worried about don't hesitate, just ACT. Please call us on the Anti-Terrorism Hotline 0800 789 321 or report online by visiting www.gov.uk/ACT., external”

Assistant commissioner Mark Rowley, national lead for counter terrorism policing, has given an update on the downgrade in the UK terrorist threat level.

Image source, PA

Neil Basu, the Metropolitan Police's senior national co-ordinator for counter terrorism, says that investigators are keeping an open mind over the number of people involved in Friday's incident.

He says: "At this stage we are keeping an open mind around whether more than one person is responsible for the attack and we are still pursuing numerous lines of enquiry and at a great pace.

"The Metropolitan Police and its partners across the Counter Terrorism Policing Network have been working around the clock and through the night to identify, locate and arrest those responsible for this cowardly crime."

Image source, Getty Images

Home Secretary Amber Rudd says that the police have made "good progress" on their investigation into the bombing on a Tube train on Friday.

Home Secretary Amber Rudd says that over the next few days the military will return to their original positions.

Military personnel have been supporting the police following the Parsons Green bombing on Friday.

Ms Rudd made the announcement as the UK terrorist threat level was reduced from critical to severe.

She says: "The Joint Terrorist Analysis Centre which reviews the threat level that the UK is under have decided to lower than level from critical to severe."

She says that severe still means that an attack is highly likely "so I would urge everyone to be vigilant but not alarmed".

Scotland Yard has confirmed that a search is taking place at a residential address in Stanwell, Surrey, in connection with the arrest of a 21-year-old man in nearby Hounslow yesterday.

From the MI5 website:, external

• LOW means an attack is unlikely
• MODERATE means an attack is possible, but not likely
• SUBSTANTIAL means an attack is a strong possibility
• SEVERE means an attack is highly likely
• CRITICAL means an attack is expected imminently

The terror threat level is being reduced from "critical" to "severe", Home Secretary Amber Rudd announces.

Image source, Reuters

Our correspondent Kathryn Stanczyszyn is in Sunbury-on-Thames, where investigators are still searching a house where it's thought a Parsons Green suspect lives.

She says one resident was told by police that activity at the house could last several days.

There is a semi-permanent cordon taking in the property that is being searched as well as seven houses on each side.

Our correspondent says residents are distressed by what has happened, but are happy they have been allowed back into their homes.

Raffaello Pantucci, director of international security studies at the Royal United Services Institute, told BBC News: "That they have left it at critical is possibly a reflection of the fact that they have not got total clarity on what exactly has taken place. If they think they have disrupted the bomb-maker they may be looking at other people out there. And if you look back at recent history, there are often copy-cats - people who use an attack as a springboard to launch something they have been thinking about for some time."

Both suspects arrested in connection with the Parsons Green attack are being held under section 41 of the Terrorism Act 2000.

This law gives police the power to arrest someone suspected of terror-related offences without a warrant.

It also allows police to detain suspects without charge beyond the four days allowed for suspects connected to other crimes.

The maximum period of pre-charge detention has varied but currently stands at a maximum of 14 days.

Detention must be reviewed at 12-hour intervals during the first 48 hours.

After that, warrants for further detention must be obtained from a court.

Following the 7/7 bombings in 2005, the government attempted to get the maximum period of detention without charge extended to 90 days, but the proposal was defeated in the House of Commons.

Forensic teams are searching a property in Hounslow, west London, following the arrest of a second man in connection with the Parsons Green bombing on Friday.

Police have put a cordon up around an area containing the house. People have been told to stay in their homes.