AMESBURY (AFP) - The two Britons exposed to nerve agent Novichok spent last Friday (June 29) in Salisbury before falling ill a day later and being taken to hospital in critical condition, according to their friend.

Salisbury is the southern English city where former Russian spy Sergei Skripal and his daughter were found poisoned back in March - by the same nerve agent.

The latest victims of the poison were named by their friend Sam Hobson, 29, as Mr Charlie Rowley and Ms Dawn Sturgess.

Mr Hobson said that Ms Sturgess was living in a homeless hostel in Salisbury and Mr Rowley was a drug user who lived in Amesbury, a small town about 13km north of Salisbury.

"We were all in Salisbury... we went in lots of different shops and went to Elizabeth Gardens to have a drink, it was a nice summer's day," said Mr Hobson said.

Then his friends "went off to have a chat".

Hours later, an ambulance was called at around 0915 GMT to treat a woman who had lost consciousness at a house in Muggleton Road in Amesbury, where Mr Hobson said Mr Rowley lived.

When Mr Hobson turned up there last Saturday morning, he was met by "loads of ambulances", firemen and emergency service crews in protective clothing.

Mr Rowley told him Ms Sturgess had complained of headaches and then collapsed with "foam coming out of her mouth".

"He called the ambulance because she stopped breathing," he said.

After the paramedics left, Mr Hobson and Mr Rowley went to a Boots pharmacy, where Mr Rowley wanted to collect a prescription.

They then stopped for a meal at a Baptist church before returning to Muggleton Road, where Mr Rowley fell ill as he was packing a bag to take to his girlfriend in hospital.

PANICKED CALL

"He started feeling really hot and sweaty... so he went and had a shower, he was in his bedroom for a while and then he came out and felt a bit weird and started acting all funny," said Mr Hobson.

"He was sweating loads, dribbling, and you couldn't speak to him.

"He was making funny noises and he was rocking backwards and forwards and there was no response from him, he didn't even know I was there. It's like he was in another world, hallucinating."

A panicked Mr Hobson called an ambulance at around 1430 GMT.

Police initially assumed the couple had taken contaminated drugs, a claim immediately rejected by Mr Hobson, saying that Ms Sturgess "doesn't take drugs". He believes they must "have gone somewhere contaminated" in Salisbury.

Samples were taken from the couple on Monday (July 2) "due to concern over the symptoms" and sent to the military laboratory at nearby Porton Down, according to head of counterterrorism Neil Basu.

Late on Wednesday (July 4), Mr Basu said tests had shown the pair had been exposed to Novichok, the same nerve agent that poisoned Yulia and Sergei Skripal in Salisbury on March 4.

In the town, the Queen Elizabeth Gardens park and a rubbish bin outside the John Baker House homeless shelter were cordoned off, with the shelter evacuated on Thursday (July 5).

The hostel is a short walk away from Zizzi's - the restaurant where Mr Skripal and his daughter had their last meal before falling ill.

In Amesbury, the Baptist church centre, the Boots pharmacy, and the house in Muggleton Road were also taped off.

More than 100 counter-terror detectives are working on the case, in addition to the local police force.

According to the latest police statement, no one else has displayed any symptoms with the risk to the public "low", although big questions remain as to the source of the contamination.