Britain's intelligence laws should be reviewed in the wake of the eavesdropping row, former home secretary David Blunkett has said.
The Labour MP said spy agencies could get "carried away" demanding new powers unless they were challenged.
A high-level commission should consider the impact of new technologies and how laws like the Regulation of Investigatory Powers Act 2000 (Ripa) could be "trimmed", he insisted.
The comments, in an interview with The Guardian, came amid claims that the UK has been running a listening post in Berlin.
The Independent said leaks from former US spy Edward Snowden suggested GCHQ maintained the operation in the German capital even after the Americans pulled out.
Mr Blunkett, home secretary during the 9/11 attacks and criticised by some as too authoritarian, said the Government came under enormous pressure from the secret services.
"Human nature is you get carried away, so we have to protect ourselves from ourselves," he said. "In government you are pressed by the security agencies. They come to you with very good information and they say, 'You need to do something'.
"So you do need the breath of scepticism, not cynicism, breathing on them. You need to be able to take a step back.
"If you don't have this, you can find yourself being propelled in a particular direction."
He said a high-level review by specialists was the best way to update laws.
"I don't like prolonged, highly expensive commissions, especially if they are chaired by judges," Mr Blunkett said. "We seem to have overwhelming faith in judges.
"We need a process of finding common ground and a solution. You need people with some knowledge and expertise."
He said Ripa, introduced under the Labour government, was meant to "provide a framework for what was a free-for-all in a growing but little understood area".
But technology had moved so fast that the law was now being used in unforeseen ways.
"We were moving into an entirely new era," he said. "We were at the very start of understanding what we were dealing with, and understanding the potential.
"You have to have constant vigilance and return to these issues on a regular basis because the world changes and you should be prepared to change with it.
"I think Ripa needs trimming back. It is being used for things for which it was never intended."
Mr Blunkett said government should "seek to retain things only if they have some usable purpose".
"Collecting and maintaining data that you can never use is a futile exercise that causes distress without results," he said.
"The present coalition came into power with a remit to try to scale back the operation of the state, but it has struggled just as badly as the previous government. I think this indicates the enormity of the issue and how difficult it is."
He insisted the intelligence agencies should welcome greater scrutiny.
"If the climate is such that people are ultra-suspicious, not only does it make it difficult to have a sensible debate, but it also means that the very big players in the intelligence community don't want to co-operate," he said.
"Once they don't want to co-operate then you are into having to force people to do things, and you get into much deeper water.
"So from the point of view of the security services it makes sense to have a greater degree of understanding and public support."
Mr Blunkett said one of the central problems was how to protect British people from surveillance by "friendly" foreign agencies, such as GCHQ's US counterpart, the National Security Agency.
"We need to examine how we are going to provide British people with protections from friendly foreign agencies who want to surveil here," he said.
"At the moment we aren't offering the same protections that they have from our domestic agencies, in terms of sign-off and warrants. We should try to work out what our stance is and we as a country haven't made any progress on that."