BLOOD samples which were taken from a "small number" of people last year feared to have been exposed to Novichok have turned up negative, police say.

A statement from the Metropolitan Police read: "Counter terrorism detectives can confirm that forensic tests carried out on blood samples, which were taken from a small number of people back in March 2018, have found no traces of Novichok.

"The individuals concerned were contacted by detectives last month to seek their permission in order to carry out the forensic tests on the blood samples.

"This was done after similar tests confirmed this summer that traces of the nerve agent were present in a blood sample (also taken at the time) from a second Wiltshire police officer."

It added: "These forensic tests have been carried out as part of what remains an ongoing investigation, which has been unprecedented in its complexity and scale and has involved thousands of exhibits.

"Officers continue to work closely with scientists and experts to meticulously and methodically review and examine the evidence available to us."

As previously reported, two men known as Alexander Petrov and Ruslan Boshirov are wanted by UK police for carrying out last year's incident.

The duo were named as primary suspects in the failed assassination of ex-Russian spy Sergei Skripal, who along with his daughter daughter Yulia survived being poisoned last March.

They made a full recovery.

However, local Dawn Sturgess died after coming into contact with the Novichok nerve agent after she and her boyfriend Charlie Rowley found the perfume bottle used to contain the deadly substance.

The force continues to appeal for any information regarding these two men whilst they were in the UK between 2 March and 4 March 2018. Anyone who knows them or saw them should call police in confidence on 0800 789 321 or email salisbury2018@met.police.uk