BRITISH counter terrorism police have taken over the investigation into the suspected poisoning of former Russian double agent Sergei Skripal and his daughter Yulia.

Metropolitan Police assistant commissioner Mark Rowley confirmed that his specialists were leading the probe as it had "specialist expertise" to do so.

Despite counter terrorism officers taking over the incident has yet to be classed a terrorism.

Metropolitan Police assistant commissioner Mark Rowley told BBC radio: “It’s a very unusual case and the critical thing is to get to the bottom of what’s caused these illnesses as quickly as possible.

“If necessary we will bring that investigation into the counter terrorism network. We’re doing all the things you would expect us to do, we’re speaking to witnesses, we’re taking forensic samples at the scene, we’re doing toxicology work and that will help us to get to an answer. I can’t say any more at this stage.”

When asked about a series of suspicious Russian-linked deaths in Britain, Mr Rowley said: "We have to remember: Russian exiles aren't immortal, they do all die and there can be a tendency to conspiracy theories. But likewise we have to be alive to the fact of state threats," before referring to the murder of Alexander Litvinenko.

Mr Rowley added, that at the moment, the key to the inquiry is to "get to the bottom of what caused this".

Richard Walton, the former head of Scotland Yard's counter-terrorism command, said that "if this is state-sponsored terrorism and it looks entirely possible, then it will have grave consequences for UK Russia bi-lateral relations".