Salisbury police only realised the significance of the Skripal poisoning when they Googled the victim, an officer involved in the investigation has revealed on the anniversary of the Russian nerve agent attack.

The first police on the scene of the Novichok attack against the Russian ex spy and his daughter said it was only after finding Sergei Skripal’s name online that they realised “it could be something bigger”.

Sergeant Tracey Holloway told BBC News the police knew “relatively early” that the Skripals were both going to intensive care. But initially the police thought their collapse had been caused by a drugs overdose.

"The paramedics said they weren't sure what it was and we didn't know what they were suffering with," she said.

"They weren't dressed in the way I would expect a drug user to be, so I wasn't really sure what we had."

"It was actually another CID officer who had Googled his name and then said, 'Tracey, do you want to come and have a look at this?',” she added.

"It was at that point that we got the link to the Russians side of things. And at that point we thought this could be something bigger than what we believed could be a drugs overdose."