Prime Minister David Cameron is satisfied with the way the work of the intelligence services is overseen, despite concerns being raised by senior Liberal Democrats in the wake of disclosures about the collection of communications data by the Government's secret eavesdropping station GCHQ.
Nick Clegg is seeking a rethink of the way politicians oversee the agencies and Business Secretary Vince Cable said he had concerns about the level of scrutiny.
But the Prime Minister's spokesman said there was no official Government review and Mr Cameron believed the current system works well.
Mr Cable called for "proper political oversight" of the intelligence services and said The Guardian newspaper had performed "a very considerable public service" in publishing secret material leaked by whistle-blower Edward Snowden, which revealed the extent of mass surveillance programmes operated by the US National Security Agency and Cheltenham-based GCHQ.
The comments came as a senior Whitehall security expert said that the Snowden leaks amounted to the "most catastrophic loss to British intelligence ever".
Sir David Omand, the former head of GCHQ who was once homeland security adviser to Number 10, said the leak of tens of thousands of files by the former US intelligence operative eclipsed the Cambridge spy ring, which saw five university students recruited as Soviet spies.
Earlier this week, MI5 head Andrew Parker warned that the Snowden leaks were a "gift" to terrorists, by exposing the ''reach and limits'' of the GCHQ listening post. His comments sparked criticism in some quarters of The Guardian's decision to give Snowden publicity.
But Mr Cable defended the newspaper, telling BBC Radio 4's Today programme: "I think The Guardian has done a very considerable public service. I think Mr Snowden's contribution is twofold, one of which is a positive one - which is whistle-blowing - and the other of which is more worrying, that a large amount of genuinely important intelligence material does seem to have been passed across.
"The conclusion that Nick Clegg came to and set out this morning is that we do need to have proper political oversight of the intelligence service and arguably we haven' t done until now.
"What they did as journalists was entirely correct and right. Mr Snowden is a different kettle of fish."
Mr Cameron said yesterday: "If people want to suggest improvements I am very happy to listen to those, but as far as I can see we have a very good system."
His spokesman said: "It is open, of course, to anyone on the National Security Council to go and speak to the agencies, discuss with them, ask questions about what they do. Of course that is open to anyone on the National Security Council, in fact any privy councillor."
But he stressed: "There is not a Government review."
Aides to the Deputy Prime Minister told The Guardian that Mr Clegg is considering how to update the legal oversight of Britain's security services and would be calling on experts to discuss the implications of new surveillance technologies for public accountability and trust.
Detailed information about the activities of GCHQ was contained in the files leaked by Mr Snowden, in what Sir David said was a bigger security breach than the Cold War Burgess and Maclean case.
Sir David told The Times that British officials assumed the information released by Mr Snowden was being analysed by Russian and Chinese spy agencies.
"You have to distinguish between the original whistle-blowing intent to get a debate going, which is a responsible thing to do, and the stealing of 58,000 top-secret British security documents and who knows how many American documents, which is seriously, seriously damaging," he said.
"The assumption the experts are working on is that all that information or almost all of it will now be in the hands of Moscow and Beijing. It's the most catastrophic loss to British intelligence ever, much worse than Burgess and Maclean in the 1950s."
Donald Maclean and Guy Burgess were among five people who passed information to the Soviet Union during the Second World War and at least into the early 1950s.
Mr Snowden, who is in Russia, leaked information to the Guardian in May that revealed mass surveillance programmes such as the NSA-run Prism and GCHQ's Tempora.
Under the £1 billion Tempora operation, GCHQ is understood to have secretly accessed fibre-optic cables carrying huge amounts of internet and communications data and shared the information with the NSA.
Nigel Inkster, a former assistant chief of MI6, said he understood there was a "real possibility" that people could have been put at risk as a result of the leaked information.
He told BBC Radio 4's World at One: "I don't know and I'm not sure anybody knows entirely exactly how much material Edward Snowden stole from the NSA systems but it is clearly a massive amount of material, i t seems to have been done on a pretty indiscriminate basis and there are, I think, quite convincing indications that there is an awful lot of operational detail there about on-going activities which risk being compromised because of what he has done.
"Apart from that what you have is the revelation of some very complex, sophisticated and expensive to develop generic capabilities."
Mr Inkster warned that terror groups would now be much more aware of communications vulnerabilities and have a much better capacity to assess the risks.
He added: "Assessing the damage and working out how to mitigate that damage I think is going to be a major task and I'm not even sure if it will ever be fully completed."
Sir Francis Richards, a former GCHQ director, suggested that oversight of the intelligence agencies could be improved and raised concerns that a former foreign secretary, Sir Malcolm Rifkind, was chairman of the Intelligence and Security Committee.
He told World At One: "Public confidence in the agency is absolutely vital, they can't operate without it.
"If they don't have confidence, if the public doesn't have confidence, in the oversight mechanisms that we have then clearly we need to ask oursleves how they can be improved.
"For a start, I think it's probably not a very good idea that a former senior minister in a Conservative government is the current chair of the intelligence and security committee."
Sir Malcolm said it was an "entirely reasonable" point of view but add that, unsurprisingly, he did not share it.
"We are completely bi-partisan," he told the programme.
"We are now responsible for deciding whether the intelligence agencies ever do anything dumb or stupid or illegal and, if they do, we are prepared to be very, very brutal with them."