CHAN: At what point did you decide to tell all? SHAYLER: I knew British taxpayers’ money was being used to pay for the [attempted] assassination of Colonel Kaddafi which had gone wrong, and killed innocent Libyan civilians. I felt I had to report that to the British public to ease what I had on my conscience.

Why didn’t you go to the police rather than the newspapers? I had a great fear that there would be a cover-up. And since the articles came out, all we’ve seen is a government cover-up. My instincts were to get these things into the open to try and institute a debate about the future of our intelligence services.

You knew that taking cash for your story would put you up for criticism. The only reason I took that cash is because I was living abroad in extraordinary circumstances. There is no legal group for whistle-blowers to go to in Britain. I asked for £20,000 to be able to go abroad and carry on backing up my case.

Can there be secrets in a democratic society? The Americans have managed to find a great balance between the right of the public to know and the right to work in secrecy when it’s necessary.

So when is it necessary? When you’ve got to protect the identity of secret agents, and sensitive operational techniques. But once those things are finished and people are put in prison, is there really a need to keep that secret forever? M.I.5 has files dating back to 1909. It may be embarrassing to M.I.5 when it comes out, but embarrassment’s different from damaging national security.

So should there be some form of an Official Secrets Act? Is this compatible with the Human Rights Act? Absolutely. The Americans have this basically. Intelligence officers are allowed to go to Congress and raise concerns with democratically elected officials. You’re not even allowed to do that in M.I.5. We have an extremely complacent secret culture that prides its secrecy above anything else, including the public right to know, including the law.

What do you ultimately want to happen to the intelligence services? Ultimately you have to have parliamentarians controlling the intelligence services rather than the government. It’s too dangerous at the moment. The government is able to collude with the intelligence services, to prevent two M.I.6 officers’ being brought to justice for their part in conspiracy to murder. This is corruption of the highest order. Everyone in Britain should be concerned to know whether the government is lying to them or not. We’re coming up to a general election. What is the point of voting if you don’t know if the government is lying or not?

What are you going to do when this is all over? I’ve been bitten by the campaigning bug because I’ve realized that there’s precious little protection of our rights in Britain. I will stand against [Prime Minister] Tony Blair in the general election because I think he’s let down the people of his constituency.

How would you advise would-be whistle-blowers? My view is we should get these things out in the media because Parliament and the government have shown no inclination to investigate what I’ve said. As long as you have every regard for protecting national security, you should be free to speak out about abuse in the intelligence services.