Hearing someone plotting a crime or terrorist attack can be compelling evidence. Britain's refusal to allow recordings to be used as evidence is about to change with the recommendation of the cross-party group of Privy Councillors that intercept evidence should be admissible. The argument, that intercepted recordings can provide evidence, has been deemed a benefit that outweighs the risks. As the committee, under Sir John Chilcot, agreed, cases of organised crime and terrorism "require the best evidence is made available".

Hearing someone plotting a crime or terrorist attack can be compelling evidence. Britain's refusal to allow recordings to be used as evidence is about to change with the recommendation of the cross-party group of Privy Councillors that intercept evidence should be admissible. The argument, that intercepted recordings can provide evidence, has been deemed a benefit that outweighs the risks. As the committee, under Sir John Chilcot, agreed, cases of organised crime and terrorism "require the best evidence is made available".

The intelligence services have argued using this evidence in trials could reveal some of their methods. The Chilcot committee has addressed this by recommending conditions on the use of intercept evidence, including the intercepting agency having a veto on the use of material. There are concerns that edited transcripts from hours of recording may be used out of context and there are recommendations that measures must be taken to avoid the prosecution "cherrypicking".

The impracticability of transcribing communications will prevent the defence from being able to demand complete transcripts. They will not be able to go on "fishing expeditions", but it has become clear that in the negotiations to follow, there must be equal safeguards for prosecution and defence. The recommendation that material should not be retained for significantly more or less time than needed for operational purposes requires fine-tuning. There are practical considerations, not least what will happen in Scotland. Public interest immunity hearings recommended as a safeguard for the security services have no counterpart in Scots law. A recommendation for such a system is under consideration. This is an area where there is an argument for the law across the UK to be broadly similar.

Civil liberties campaigners have been supportive of the use of intercept evidence because they see it as weakening the case for extending the time limit for detention without charge. There will be some cases where allowing intercept evidence will enable a prosecution to be brought sooner. That is welcome, but not a complete solution.

Lord Carlile, the independent reviewer of counter-terrorism legislation, is a senior voice warning intercept evidence may be led in "very few" cases. It will not be the "silver bullet" campaigners hope, yet when all of us are under surveillance, it is a tool to be used judiciously against organised crime and terrorism - but the rights of the individual and the security services must be safeguarded.