Sam Hancock
Live reporter

Police say they're combing through hundreds of hours of CCTV footage as their suspect in an alkali attack, Abdul Shokoor Ezedi, remains at large.

• To catch up on what else the Met told us a little earlier, at an off-camera briefing, head here
• To keep reading about last Wednesday's attack, in which a mother and her two young daughters were doused with a corrosive substance, read this
• And to understand everything we know about what happened last week - and the nationwide search since - read our explainer

That's it from us on this page, which was written by Jacqueline Howard, Christy Cooney and Callum May - and edited by me.

Esme Stallard
Science reporter

During that update, police said they had analysed the substance used in the attack on Wednesday, and had narrowed it down to two potential very strong alkalis.

It's worth remembering that alkalis are not difficult to come by. They can be found in many common household items from bicarbonate of soda to drain cleaner.

But not all of these substances are harmful to human health - it depends how strong they are.

Weak alkalis are unlikely to cause any harm. In fact they can be consumed - such as baking soda in cakes.

It is products that contain strong alkalis like sodium hydroxide that cause damage, external, these are most commonly used in strong household cleaners and the paper industry.

A common misconception is that is it only acids which are corrosive, but strong alkalis like this can also cause serious damage to humans.

Depending on how long you are exposed, the type of exposure (ingestion or skin contact) and the dose it can cause severe burns to tissue, accumulation of fluid in the lungs and blindness.

Image source, Getty Images

Image source, Metropolitan Police

We've just had an update from the Metropolitan Police about their manhunt for Abdul Shokoor Ezedi, which is in its fifth day.

If you missed it, or need a recap, here are six key things we learnt:

• A 22-year-old man was arrested this morning for assisting an offender - he was interviewed by police in south London and later released on bail
• The 31-year-old mother, attacked with an alkaline substance on Wednesday, has facial injuries that will impact her for the rest of her life - police say she may lose sight in her right eye
• Ezedi was last seen in the Southwark Bridge area of London at 21:50 GMT on Wednesday - a little more than two hours after the attack
• Police say they are not currently searching the River Thames for Ezedi
• The motive behind the attack is still unclear, but police say Ezedi is not the father of the children he's also accused of attacking
• Police are combing through hundreds of hours of CCTV footage to discover Ezedi's whereabouts - they say he's been using a bank card to move around London's tube network, but it hasn't been used since late on Wednesday

The focus of the investigation remains London and Newcastle, police tell reporters at an off-camera briefing, which we're almost done updating you on.

Det Supt Sewell says the Met are being well supported by Northumbria Police and the British Transport Police. Those forces are working on gathering CCTV in Newcastle, he says, and looking for anyone who may have known Ezedi in Newcastle.

Cdr Savell, also from the Met, adds that the manhunt continues at a considerable pace, with hundreds of officers involved - including from counter terrorism.

He reiterates that Abdul Shokoor Ezedi is considered a very dangerous offender.

Police tell the briefing that it's always more difficult to crack a manhunt when the suspect doesn't have a mobile phone with them.

Ezedi's phone - which police have - has been "comprehensively analysed", Dep Supt Sewell says, as has the substance used in the attack - which has been narrowed down to two potential very strong alkalis.

He also lays out two police theories, which he says are being considered:

• Ezedi has come to some harm
• Someone is looking after him

Dep Supt Sewell says if Ezedi is being kept at one address, and being provided with food and water by someone, then the search could take several weeks.

Dep Sup Sewett says it is possible that the 31-year-old mother, injured in the attack, may lose sight in her right eye.

He says police still don't understand why she or her children were attacked last Wednesday.

Here's some more from that police briefing, which happened off camera and we're bringing you updates on now.

Ezedi was using a bank card to travel around London's tube network, but it hasn't been used since Wednesday night, Det Supt Sewett says.

In relation to the sighting of Ezedi on Southwark Bridge, Det Sup Sewett says police are not currently searching the River Thames.

Det Supt Rick Sewett, from specialist crime, was also at the briefing - he says the new CCTV images of Abdul Shokoor Ezedi will be released soon.

He also says police are still trying to establish how long Ezedi and the injured woman have known each other and what sort of relationship they had.

But he confirms that Ezedi is not the father of the woman's children who were hurt in the attack.

Police say they have new CCTV images showing Ezedi in the Southwark Bridge area at 21:50 on Wednesday.

Previously, the last sighting of him was at Tower Hill underground station, at 21:33, the same day.

Cdr Savell says hundreds of members of the public from London and across the country have contacted the police following an appeal for information.

People can contact the police via the hotline on 020 7175 2784, he says, reiterating that the public are advised not to approach Ezedi and to call the police instead.

Cdr Savell says the mother who was injured in the attack remains sedated and in a critical but stable condition.

He adds that she has significant facial injuries, which will be there for the rest of her life.

Police have just given an update to reporters, off camera, about the hunt for Abdul Shokoor Ezedi. We're going to bring you what they told us in the next few posts.

Met Police Commander Jon Savell says that early this morning, a 22-year-old man was arrested for assisting an offender.

He was taken to a police station in south London, where he was interviewed before being released on bail.

“If people are harbouring Ezedi, they do potentially commit an offence and we take that very seriously and we will take action," Savell says.

Image source, Metropolitan Police

We know of five search warrants that have taken place in the search for the suspect - two in east London and three in Newcastle, where he lives.

Police said on Friday they had uncovered significant evidence.

At one of the Newcastle addresses, empty containers were found with corrosive warnings.

Forensic tests were said to be ongoing to see if the containers found in the flat held the substance used in the attack.

Here's everything we know about Abdul Shokoor Ezedi's movements in the lead up to, and after, Wednesday's attack:

• Ezedi left Newcastle in the very early hours of Wednesday morning, and travelled to London
• At 06:30 he was in the Tooting area, there was a further sighting of his vehicle at 16:30 in Croydon and then at about 19:00 he was in the Streatham area
• The alkali attack took place at 19:25 in Clapham, and at 19:33 Ezedi boarded a train at Clapham South tube station
• At 20:00 he was at King's Cross station and about 45 minutes later he was captured on CCTV footage at Tesco with significant facial injuries
• We now know that at 21:33, he got off a tube and exited Tower Hill underground station in east London

CCTV, courtesy of Sky News, appears to show the attack carried out in Clapham, south London, on Wednesday night.

Abdul Shokoor Ezedi escaped the scene on foot, and was later spotted in north London and various tube stations.

BBC correspondents describe how the incident and aftermath unfolded:

What happened in Clapham? Initial reports said a 31-year-old woman and her two young girls - aged three and eight - were injured after a "corrosive substance" was thrown at them on Lessar Avenue, near Clapham Common, at 19:25.

What do we know about the suspect? Police named the suspect as 35-year-old Abdul Shokoor Ezedi, thought to be from Afghanistan and who lives in Newcastle, north-east England. Detectives believe he's known to the family who were injured in Clapham, but said last week they were not yet clear on the relationship.

Where is he? The attack took place at 19:25 last Wednesday - he then boarded a train, at 19:33, at the nearby Clapham South tube station. At 20:00 he was at King's Cross station, and the last confirmed sighting was of him exiting Tower Hill tube station at 21:33.

Are the victims still in hospital? Yes. The mother is still "very poorly and is sedated", police have said, but her daughters' injuries were not as bad as first thought. The five responding police officers who were injured were taken hospital and later discharged, as were three women who came to the aid of the family.

• You can read more on all these questions here

Image source, Metropolitan Police

Armed officers were called to Manchester Piccadilly rail station on Saturday night, after a tip-off suggesting Abdul Shokoor Ezedi was on a train pulling in to the station.

They searched a Northern Train service from Sheffield, which arrived at the city's main train station shortly after 23:40 GMT. It turned out to be a false alarm.

A statement form British Transport Police confirmed:

With the latest information we have, Ezedi was last sighted at London’s Tower Hill tube station at 21:33 on Wednesday.

Good afternoon.

Police are continuing to search for Abdul Shokoor Ezedi, who’s wanted after a woman and her two daughters were attacked last Wednesday.

The injured 31-year-old, known to Ezedi, is in a critical but stable condition in hospital. Her daughters are recovering.

Ezedi fled the scene in Clapham, south London, on foot. He has been seen on CCTV with a serious facial injury and there's a £20,000 reward for information leading to his arrest.

Stay with us for the latest updates.