Portsmouth university lecturer: Russia has long tradition of eliminating enemies

Dr Paul Flenley, a senior lecturer in politics and international relations at the University of Portsmouth, said Russia and its secret police had a ‘code’ to avenge treachery.

It comes as the Russian double agent and his daughter fell critically ill in Salisbury on Sunday.

Dr Flenley said: ‘It’s all speculation at the moment, but there’s a long tradition of Russia eliminating its enemies.

‘The secret police are well trained. There’s an assumption you can’t escape, there’s a code and if you break it, if you betray them, they will get you – it’s part of their discipline.’

But Dr Flenley said Russian president Vladimir Putin was not necessarily the source of such acts.

He added: ‘There’s a tendency to assume everything is orchestrated by Putin, and of course he likes that, it amplifies his power. But there are business groups and mafia-like groups who could be seeking revenge.’