Scottish devolution pledge stands insists No 10
Downing Street has made it clear that David Cameron's Scottish devolution pledge does not depend on giving more powers to English MPs at the same time.
Mr Cameron vowed to give tax-raising powers to the Scottish Parliament "in tandem" with moves to restrict Scottish MPs from voting on English matters.
But No 10 sources insist that "one is not conditional upon the other".
Labour leader Ed Miliband said he and other leaders must honour their promise to Scottish voters.
Mr Cameron took Labour by surprise on Friday when he announced plans to end the anomaly which allows 59 Scottish MPs to vote on England-only legislation, such as health and education.
He is under pressure from Conservative backbenchers angry at the way he, Ed Miliband and Nick Clegg teamed up to offer more powers to Scotland in the run-up to Thursday's independence referendum.
The pledge was labelled "disgraceful" and "panicky" by former leadership rival David Davis, while ex-Cabinet minister Owen Paterson said MPs had been kept in the dark about the plan.
Mr Cameron has invited some of his most vocal backbench Tory critics to an "English votes for English laws" summit on Monday at his country residence Chequers as he seeks to head off a potential rebellion.
Scottish First Minister Alex Salmond said the Scots had been "tricked" by the pledge to agree, in draft form, new powers for Holyrood on tax and welfare within six months of the referendum result - in which voters rejected independence.
Mr Salmond claims the timetable for delivering more powers in the event of a No vote is slipping "shamelessly", since Mr Cameron cannot guarantee his backbenchers, who want more power for English MPs, will vote for it.
In other developments:
- The prime minister is reported to have invited senior Tories to Chequers on Monday to discuss the devolution plans
- Constitutional expert Sir William McKay said making changes in Scotland and England at the same time would be a "very big job"
- Ed Miliband rules out Gordon Brown returning to frontline politics after his key role in the referendum campaign but holds out the prospect of Alistair Darling doing so
- The SNP says it has signed up 8,000 new members since the referendum vote, while Mr Salmond reveals plans to write a book about the campaign entitled '100 days'
- Labour politicians in Wales are urging party leaders to back a fair deal over funding and powers in any discussions on further devolution within the UK
- More than 1,000 people attend a special Church service in Edinburgh to celebrate Scotland's "shared values" and "common purpose"
- Half the Scottish cabinet publicly back Alex Salmond's deputy, Nicola Sturgeon, to replace him as SNP leader
Some in the Labour Party fear Mr Cameron's surprise announcement on England-only votes is a "trap" that could undermine a future Labour government, which would rely on its Scottish MPs to give it a majority on key votes.
Mr Miliband rejected this argument in an interview on the BBC's Andrew Marr programme, saying most Labour governments had also had a majority in England.
Analysis by political correspondent Ross Hawkins
Will Scotland only get more powers in Holyrood if Scottish MPs get fewer votes in Westminster?
It could sound that way. David Cameron said the two matters should be decided "in tandem".
His chief whip Michael Gove said it would be "impossible to move forward" without being certain of change in Scotland and England.
Yet on the idea of swiftly drawing up plans that could stop Scottish MPs voting on England-only laws, Ed Miliband disagrees. It feels a lot like politics as usual.
The pre-referendum arrangement between the Westminster parties was designed to look very simple. Since the vote, things have grown complicated.
And yet voices in all three parties are clear - they will make good their vow to Scotland. No ifs. No buts. The Scottish people will hold them to it.
He refused to be drawn on whether he supports the principle of England-only votes at Westminster, only saying that he was not against "greater scrutiny" by English MPs.
The BBC's assistant political editor Norman Smith said Labour was looking at "a grand committee" of English MPs to consider English laws.
Mr Miliband repeated his call for a national debate on the constitution, saying major changes of the kind being proposed by Mr Cameron could not be drawn up "on the back of a fag packet".
'Together, not apart'
"Let's not drive our country apart because David Cameron thinks it is an opportunity for him to do it. Let's keep our country together and it is very important we do it (change) in the right way."
He suggested the pledge of more powers for Scotland should be dealt with separately, telling Andrew Marr that the prime minister had not raised the English issue with him before they signed their joint "vow" with Lib Dem leader Nick Clegg.
He said he was "open" to the idea of empowering English MPs in Westminster, but opposed a separate English Parliament.
"People right across the UK will say David Cameron made a promise. He did not make a conditional promise. He made a clear promise and he is going to be kept to that.
"I know David Cameron will want to honour that promise....For my part, I am going to keep the promise I made…We are going to deliver on the pledge, no ifs not buts."
The head of the Better Together campaign, Alistair Darling, said the pledge of extra powers for the Scottish Parliament is "non-negotiable".
"It was promised, it has to be delivered," he told the Andrew Marr show. "Anyone who welches on that will pay a very high price for years to come."
And Lib Dem Scottish Secretary Alistair Carmichael said the government would be sticking to the undertakings given in respect of new powers for Scotland.
"We've set out the timetable for the Scottish reform - there can be no movement from that timetable," he told BBC Radio 5Live's Pienaar's Politics.
Tory chairman Grant Shapps said there would be no "reneging" on the parties' Scottish commitments but a new English settlement had to be reached "at the same time".
"We fought for a no vote (in Scotland) even though we don't benefit," he told Dermot Murnaghan on Sky News. "We put politics aside. Ed Miliband needs to put politics aside."
And Justice Secretary Chris Grayling said Holyrood should not receive more powers while Scottish MPs can still "shape the destiny" of the NHS and schools in England.
He told the Sunday Telegraph that this would amount to a "travesty of democracy, and would be regarded with fury by the English".