The government will not "ram legislation through Parliament" to increase monitoring of emails and web usage, Nick Clegg has said.

The deputy prime minister said the proposals would be "published in draft" first to allow them to be debated.

Earlier, the Home Office said it planned to "legislate as soon as parliamentary time allows".

Ministers say change is needed to help fight crime and terrorism, but critics warn it is an attack on privacy.

Internet service providers (ISPs) are obliged to keep details of users' web access, email and internet phone calls for 12 months, under an EU directive from 2009.

Although the content of the calls is not kept, the sender, recipient, time of communication and geographical location does have to be recorded.

The proposed new law - which the Home Office says will be brought in "as soon as parliamentary time allows" - would extend those requirements to social networking sites and internet phone services such as Skype.

'Proportionate measures'

It would also reportedly allow intelligence officers to access emails, calls and texts as they happen, without a warrant, rather than retrospectively - and would tighten up the rules around exactly what data ISPs must keep.

Analysis In the Sun this morning we had Theresa May saying we had to keep one step ahead of terrorists. Along side that, the Home Office was saying it would bring in legislation as soon as Parliamentary time allows. But before you know it, we get Nick Clegg saying, no, there'll have to be a proper debate first and any legislation will have to be preceded by a draft set of proposals. So bullish rhetoric from the Home Office and conciliatory rhetoric from Nick Clegg. Opponents of this proposal will detect the very clear sound of ministers and officials slamming on the brakes.

Mr Clegg told the BBC people should wait to see the full proposals before judging them - and insisted the content of any communications would still only be accessible with a warrant.

"There's been a lot of scaremongering, a lot of myths about in the media over the last couple of days," he said.

"Any measures will be proportionate. They will not sacrifice people's civil liberties, we will not create a new government database and we will not give police new powers to look into people's emails."

He said safeguards for privacy and civil liberties were "absolutely guaranteed", and added: "Let's be clear, we aren't simply going to ram some legislation through Parliament.

"We will make sure our proposals are published in draft, people can look at them, people can debate them because there is a legitimate debate to be had here."

A senior Home Office source said the proposal "absolutely will not be dropped or even delayed", but its "passage through the Commons is still being discussed".

The source suggested it had "not been decided" yet whether to include it in the forthcoming Queen's Speech.

BBC political correspondent John Pienaar said there did appear to have been some retreat over the timing.

He said sources close to Mr Clegg believed the issue had been mishandled by the Home Office and the deputy PM had been forced to step in to sort it out.

Meanwhile, 16 Lib Dem MPshave signed an open letterbacking the need for a public debate on the issue.

'Overkill'

Earlier, Mrs Maytold the Sunthe move will help bring "criminals, paedophiles and terrorists" to justice, and "ordinary people" would have nothing to fear.

But Chris Fox, former head of the Association of Chief Police Officers, said the idea was "fraught with danger for the innocent vast majority", not least that of misidentification, which could result from genuine criminals disguising their communications as those of law-abiding citizens.

"If you are investigating crime you have targets... it just seems to be overkill and intrusive for the 99.9% of the rest of us."

Attempts by the last Labour government to create a giant central database containing all UK web and telephone use were dropped after huge opposition, including from the Conservatives and Liberal Democrats.

But Prime Minister David Cameron said: "Let's be absolutely clear, this is not what the last government proposed and we opposed."

Peter Davies, chief executive of the Child Exploitation Online Protection Centre, gave his support to the changes, saying it was right for the government to impose some "consistency" on the data ISPs should gather.

"At the moment, when you're investigating online activity you can get lucky, but we should take the luck out of it," he said.

"We are dealing with cases at the moment where we are losing the opportunity to identify paedophiles who are preying on children because it's not always possible to get the communications data we would like."

'Checks and balances'

But, several Conservative backbenchers have attacked the proposals.

Former shadow home secretary, David Davis, said: "If they want to see all this information they should be willing to put their case before a judge or magistrate. This will force them to focus on the real terrorists rather than turning Britain into a nation of suspects."

Critics have warned that any new law could end up being used more widely than originally intended - similar to the controversial Regulation of Investigatory Powers Act, which has been used by local authorities to check on children's school catchment areas.

Labour have said the police and security services have to be able to keep up with new technology, but there must be "clear checks and balances" on what they are able to do.

Leader Ed Miliband said the issue was "very sensitive" and had been "spectacularly mishandled" by the government, leading to fears of intrusion into people's day-to-day lives.

Even if the move is announced in the Queen's Speech, any new law would still have to make it through Parliament, potentially in the face of opposition in both the Commons and the Lords.

The Internet Service Providers' Association said any change in the law must be "proportionate, respect freedom of expression and the privacy of users".