The security services have issued an unprecedented public warning

The security services have issued an unprecedented public warning that Akhmed Zakayev — an exile who is a friend of Vanessa Redgrave, the actress — is the target of a murder plot.

On their advice, the Home Secretary has fought a court battle to remove the man MI5 believe would organise the “hit”, who they say is a danger to “national security”.

But The Sunday Telegraph can reveal that judges have allowed him to stay in Britain and fight to remain here.

The case raises serious questions about how Britain can be protected from foreign threats.

The murder plot is disclosed in the wake of the attempted assassination of German Gorbuntsov, the wealthy Russian banker who was shot outside his London flat and who remains seriously ill in hospital.