Terror suspects will go free in plea bargain deal

Terror suspects could be given immunity from prosecution if they testify against their fellow plotters under "plea bargaining" reforms being prepared by Theresa May.

The Home Secretary wants to increase the number of convictions by giving extremists an incentive to cooperate with police. Sentence reductions could also be available in a further attempt to persuade terrorist detainees to reveal details of their plot.

The change could allow terrorists involved in conspiracies to commit serious atrocities in Britain to escape justice and is likely to disturb some critics.

Supporters argue, however, that it is a "pragmatic" way of bringing cases against dangerous extremists who could otherwise be impossible to prosecute. The Government's decision to seek to deploy "plea bargaining" in terrorism cases comes after concern that too many suspects are refusing to answer police questions.

Such tactics make it difficult for police to discover the full extent of complex terrorist conspiracies and networks and to amass the evidence needed to mount prosecutions.

Announcing the new approach, police minister Nick Herbert said that the aim was to expand the use of existing legal powers on "Queen's evidence" deals - introduced six years ago for use in organised crime investigations - to terrorist cases.

He said: "Sections of the Serious Organised Crime and Police Act 2005 give a statutory basis for defendants and prisoners to provide evidence ... in return for immunity from prosecution or a possible reduction in sentence.

"The Government are looking at ways in which the use of these provisions in terrorism cases to support our prosecution efforts can be increased." The Crown Prosecution Service said that 33 Queen's evidence deals using the existing legislation have been struck so far to help bring prosecutions.

Patrick Mercer, a Tory MP and former shadow security minister, said the expansion of the tactic to terrorist cases was a "welcome" step towards increasing convictions.

"This is one way of getting more terrorists into court and I am surprised it has taken the Government so long to act," he said.

Under the Serious Organised Crime and Police Act, senior prosecutors can offer an "immunity notice" to a suspect if it is deemed to be "appropriate" to assist an investigation. The legislation also empowers judges to impose a lower sentence in cases in which prosecutors have struck a written, pre-trial agreement with an offender in return for assistance.