Picture of Sergei Skripal's BMW released as police hunting poisoners focus on car

Updated timeline of victims' movements also published

Police have released an image of Sergei Skripal's car as they launch a fresh appeal for witnesses in the poisoning of the former Russian spy and his daughter, Yulia.

The Metropolitan Police believe the Skripals used the burgundy red BMW 320D saloon - registration HD09 WAO - on Sunday 4 March, the day of the attack.

Both victims remain critically ill in hospital after being poisoned with what authorities believe was the military-grade nerve agent Novichok. The UK government has blamed Russia for the attack, an accusation the state has repeatedly dismissed.

"We are learning more about Sergei and Yulia's movements but we need to be clearer around their exact movements on the morning of the incident," said Met Assistant Commissioner Neil Basu.

The police are particularly interested to hear from anyone who may have seen the car before 1.30pm on 4 March and are urging anyone who has information to call the police on 101.

Around 400 witnesses have already given statements, Mr Basu said, while detectives "have recovered 762 exhibits and are trawling through around 4,000 hours of CCTV".

About 250 specialist offers from the counter-terrorism network are working "around the clock on this case" along with hundreds of other police officers and members of the military and emergency services, said Mr Basu.

"They are making good progress in what is a painstaking investigation that is likely to be ongoing for weeks, if not months."

By releasing the image of Mr Skripal's car, police are hoping to establish more details about the movements of the Skripals on the morning of the attack.

Ms Skripal landed at Heathrow Airport on a flight from Russia at 2.40pm the previous day, according to police.

At around 9.15am on Sunday, 4 March, the red BMW may have been seen in the area of London Road, Churchill Way North and Wilton Road, in the northern part of the city, police say.

The next sighting was at about 1.30pm when the car was spotted being driven down Devizes Road, towards the town centre. Shortly afterwards, the Skripals parked the car and first visited the Bishops Mill Pub before arriving at Zizzi Restaurant at 2.20pm, leaving just over an hour later, according to the police.

The first emergency call was received at 4.15pm. Police arrived at the scene to find Mr and Ms Skripal seriously ill on a bench near the restaurant.

Detective Sergeant Nick Bailey, one of the first to respond to the incident, remains in a serious but stable condition in hospital after also being taken ill.

Mr Basu reiterated that the health risk to the public is low and that the continued presence of officers in Salisbury wearing protective clothing is "not an indication of an increased risk".