In the first Commons debate on MI5, MI6 and GCHQ, many members paid tribute to the work of the three agencies.

But Labour MPs Dale Campbell-Savours, David Winnick and Chris Mullin said the cross-party committee overseeing their activities should be given more power.

The Security and Intelligence Committee published a report on the agencies last month - the third since the committee was set up in 1994. But never before has the public had the chance to hear about its findings through MPs.

Robin Cook warns against more powers for the committee

Opening the debate, Foreign Secretary Robin Cook said the agencies did valuable work countering international drug traffickers, terrorists and fighting arms proliferation, as well as providing valuable background information for arms negotiations and for British troops abroad.

But he told MPs that changes to the Intelligence and Security Committee might be counter-productive because the security services might co-operate with it less freely.

The committee itself wants to have the power not just to oversee security services, but also to investigate them and this was one of its main recommendations, saying the change would create greater public confidence.

Witness plea

Committee member Mr Campbell-Savours urged the foreign secretary to turn the watchdog into a parliamentary select committee, with greater powers to call and cross-examine witnesses, who could be held in contempt for misleading the committee.

Dale Campbell-Savours calls for more committee power

He said: "Isn't the truth that if this committee were to be a fully fledged select committee of parliament many of the arguments that have taken place would not have to take place in the future?"

Mr Winnick said: "As long as there is a lack of proper parliamentary accountability - which is the situation now regardless of the existence of this committee - this controversy will continue one way or another and the way to resolve it is by having that type of scrutiny which we said we would in opposition."

Mr Cook said the debate was an example of how the government was indeed showing more openness. He said the government had no reason to apologise for its record on openness.

He added: "I am sure Parliament would be wise to reflect that on whether, in that move to greater openness which would come to a select committee, there may be lost some of the candour and openness with which the agencies themselves can co-operate with the present committee."

Arms threat

Committee chairman and former Tory defence secretary Tom King said arms proliferation was probably the biggest single world threat and a major preoccupation of the security services.

We demand full answers, says Tom King

He stressed that committee members wanted the service heads, when giving evidence, to give as full answers as possible, unless there were good security reasons for not doing so.

The report also considers why there are so many "whistle-blowers" such as former MI5 agent David Shayler, who is wanted in the UK to face charges under the Official Secrets Act following his revelations about his activities.

The accountability of the agencies and their ability to hold information on people, is also called into question.

The committee has also recommended an industrial tribunal be established to deal with "disaffected" members of the secret agencies.

Mr Campbell-Savours pressed on with his argument. He said: "I do not believe that oversight is fully credible while the committee remains a creature of the executive.

"The arguments in favour of select committee status are utterly overwhelming."

Former women's minister and onetime chair of the Campaign for Nuclear Disarmament Joan Ruddock demanded that she should be able to see her security file after speaking of the "long shadow" cast over her life by MI5.

The Labour MP for Lewisham Deptford told the Commons she and her family suffered intimidation by the security services after she became involved in the CND in the early 1980s.

She told MPs she had read a report in the Mail on Sunday newspaper that she had been singled by the intelligence agency as one of nine potential ministers who posed a security threat before the last two general elections.

She said she had suffered a "slur" upon her character and had no means of redressing the situation.

"I was and am a loyal citizen of this country who has done nothing more than campaign for causes in which I believed," she told MPs.

"If there is any file on me that suggests otherwise, then it is a falsehood and I should have the opportunity to correct it."