The daughter of a former Russian double agent poisoned alongside her father in a nerve agent attack is 'conscious and talking.'

Yulia Skripal was 'improving rapidly' after being exposed to Novichok on March 4 in Salisbury, Wiltshire, and is now stable in hospital, doctors said, with the 33-year-old also understood to be eating and drinking.

The BBC reports separate sources have verified Yulia is both conscious and talking.

Her father, ex-spy Sergei Skripal, 66, remains in a critical but stable condition in hospital.

One of Mr Skripal's friends has said he believes he is being kept alive by life support machines.

Mr Skripal's niece previously said she believes he only has a '1 per cent chance' of survival.

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Yulia Skripal was 'improving rapidly' after being exposed to Novichok on March 4 in Salisbury, Wiltshire, and is now stable in hospital, doctors said

Doctors said Yulia Skripal (pictured with her father) was 'improving rapidly' after being exposed to Novichok on March 4

In a statement, Salisbury NHS Foundation Trust said Yulia Skripal is 'improving rapidly and is no longer in a critical condition.'

The development could prove key to the investigation into the attack - as it may mean Ms Skripal could soon be able to tell police about the moments before she and her father collapsed in a park.

She could also potentially identify whoever carried out the attack - which is now thought to have taken place at Mr Skripal's suburban home.

The Metropolitan Police believe Mr Skripal and his daughter, who was visiting him from Russia, first came into contact with the deadly chemical at his home in Salisbury.

Detailed forensic testing revealed the highest concentration of Novichok was found on the front door.

The attempted murder investigation is continuing and, as a precautionary measure, police placed a cordon around a children's play area at nearby Montgomery Gardens.

Police have removed the front door of Sergei Skripal's home after it emerged detectives believe that is where the former spy came into contact with the nerve agent

Police said traces of the nerve agent had been found at some of the other scenes detectives have been working at, but at lower concentrations.

Detectives will now focus their inquiries in and around the address, and specialist teams will step back from some of the other areas investigated over the past few weeks.

Deputy Assistant Commissioner Dean Haydon said: 'I would like to reassure residents that we have placed the cordons around the park, and officers will be searching it, as a precautionary measure.

'I would like to reiterate Public Health England's advice that the risk to the public is low. Anyone with concerns regarding the ongoing police activity in Salisbury is encouraged to speak to the local officers or PCSOs at the locations, who will be happy to offer reassurance.'

Mr Skripal and his daughter have been patients at Salisbury District Hospital since they were discovered unconscious on a park bench close to The Maltings shopping centre nearly four weeks ago.

Wiltshire Police Detective Sergeant Nick Bailey, who was also exposed to the nerve agent, was discharged from the hospital last week.

Aerial pictures reveal the door and surrounding building have been removed with police have covered the front garden and put paneling down to walk on

A large part of the street has now been closed off, with evidence tents in the back garden

Medical director Dr Christine Blanshard said: 'I'm pleased to be able to report an improvement in the condition of Yulia Skripal.

'She has responded well to treatment but continues to receive expert clinical care 24 hours a day.

'I want to take this opportunity to once again thank the staff of Salisbury District Hospital for delivering such high quality care to these patients over the last few weeks.

'I am very proud both of our front-line staff and all those who support them.'

Early this week Viktoria Skripal, a niece of the former spy, told the BBC her uncle and cousin have only a slim chance of surviving.

She said the prognosis 'really isn't good' and revealed Mr Skripal's mother had not been told of the incident.

Mr Skripal and his daughter (left) stand outside the front door with another relative during a previous visit she made to the UK

Mr Skripal had put up a lucky horse shoe above his suburban home in Salisbury

Britain has accused Russia of being behind the poisoning - allegations fiercely denied by Moscow.

In turn, Russia has suggested that UK intelligence officers may have been involved in the poisoning.

The Kremlin allegation came as Moscow faced increasing global isolation, with at least 26 countries expelling a total of more than 130 suspected spies.

Britain insists there is no plausible alternative explanation for the attack and has dismissed the series of suggestions emanating from Moscow as nonsense.

More than 250 counter-terrorism detectives continue to work on one of the biggest investigations since the July 7 attacks in London in 2005.

Officers are trawling through more than 5,000 hours of CCTV.

No corden was placed around the house when the investigation first began earlier this month

They have seized 1,350 items, including the Skripals' car, the table and chairs where they sat for lunch and even the bench where they were found.

About 500 witnesses, including neighbours, drinkers in a waterside pub and diners in an Italian restaurant have been identified.

Traces of the nerve agent have been found at several locations, including the Skripals' BMW, but police said they are at 'lower concentrations'.

DS Nick Bailey was one of the first on the scene at Mr Skripal's house. He later fell ill

The London Road cemetery, where his wife and son are buried, The Maltings shopping centre and the Ashley Wood compound have been handed back into the control of Wiltshire Police.

A children's play area near Mr Skripal's home became the latest location closed off by police investigating the chemical weapons attack today.

It comes as police investigating the nerve agent attack removed the front door of the home where the Skripals are believed to have been poisoned.

Forensics teams have said they found the 'highest concentration' of the deadly Novichok substance at the entrance to the suburban house in Salisbury.

The discovery has led investigators to examine whether a 'poison postman' is responsible for the attack on the former double agent and his daughter.

The Zizzi restaurant visited by the Skripals before they collapsed remains cordened off

One theory is that they may have been visited by a bogus parcel van driver, postman or leaflet deliverer who exposed them to the poison.

Another is that the poison was smeared on the front door or door handle, leading to its delayed effect after they left home. Experts insist such a complex assassination would need a killer 'on the ground' to ensure it was a 'success'.

Scotland Yard said last night its focus was on the Skripals' semi-detached house on the outskirts of the cathedral city.

Residents were warned teams of detectives, forensic experts and scientists will remain for 'the coming weeks, and possibly months'.