The attempted killing of former Russian spy Sergei Skripal is a real worry and poses major challenges for British intelligence. Finding a motive remains a key question because this was a man who had been convicted for spying for Britain, pardoned, released and then targeted to be killed on British soil?

Sergei Skripal is believed to have been recruited by British intelligence back in the 1990s while serving under diplomatic cover abroad with the GRU – the Russian military intelligence.

He is thought to have provided valuable intelligence to the UK at the time – especially the identities of other undercover operatives.

But he left the GRU around 2000 and was arrested in 2004. He was then imprisoned.

After his release in 2010 in the spy swap, he will have been debriefed by British intelligence but there are few signs so far that he was involved in serious ongoing operational work.

It’s all very worrying that the Russians have the gall to assassinate someone over here with chemical weapons, Britain has got to get fucking tough on Russia.