When Parliament resumes next week, Tony Blair will face a much-reduced Labour majority in the House of Commons.
By Steve Schifferes
BBC News website reporter
With a majority of only 66, just 34 rebels could stop him in his tracks, if supported by the opposition parties.
But are there enough Labour rebels left with the reduced majority - and if so which are the issues they are most likely to rebel against?
And, just as importantly, will they be able to make common cause with a divided opposition?
The BBC Analysis and Research Unit believes a substantial group of Labour rebels has been re-elected to Parliament.
Former Cabinet minister Clare Short is a fierce government critic
The analysis suggests there are 37 hard-core rebels (who rebelled on all four key issues in the last Parliament, including student tuition fees, foundation hospitals, Iraq, and the prevention of terrorism act), and another 29 "soft rebels", who voted against the government on at least two of those four issues.
Only two hard-core Labour rebels were among the 47 Labour MPs who lost their seats - John Cryer in Hornchurch and Phil Sawford in Kettering - although several more (such as Brian Sedgemore, who defected to the Lib Dems) stood down at the last election.
On the other hand, many of the Labour losers were moderates who occupied suburban seats in the South East.
According to our analysis, there is also a looser group of about 47 MPs loyal to Gordon Brown, who have joined some of the rebellions in the past.
The Campaign Group, which co-ordinates activities among Labour rebels, has 20 members.
Targets of revolt: ID cards
There are two issues that are likely to spark a Labour backbench rebellion in the next Parliament.
Firstly, Mr Blair has made it clear he will re-introduce the ID card bill in Parliament - it fell when the election was called.
The terror bill prompted a big revolt in the last Parliament
About 20 Labour backbenchers rebelled during the second reading debate, and the civil liberties group Liberty is sure to make it one of its top campaigning issues.
The Liberal Democrats are also opposed to ID cards, but much will depend on the attitude of the Conservatives, who have flip-flopped on the issue during the last Parliament and now say that they support the idea in principle, but have practical objections to Labour's plans.
It will take a firmer line from the Conservatives, who abstained in the debate, to defeat the government on this issue.
Target of revolt: welfare reform
The other issue that is likely to spark a Labour backbench revolt is welfare reform.
Charles Clarke led an early rebellion on welfare reform
The attempt to get tough with lone parents to encourage more to go to work sparked a Labour rebellion in the first term (led by Charles Clarke).
Labour is now proposing action on the 3m invalidity benefit claimants, following a series of pilot schemes.
The other parties are more supportive of these plans, and David Willets, the Tory pensions spokesmen, endorsed Mr Brown's approach during the election (saying it was the one part of the New Deal he would not want to scrap).
This issue is how to encourage more older men to stay in the workforce for longer, given the problems of pension provision associated with an ageing workforce - but any use of compulsion would be highly controversial.
The pensions issue itself, although likely to be highly contentious in the country, may not lead to any revolts, if the government keeps to its pledge not to introduce any major new approaches without all-party consent.
It would be the introduction of compulsory private pensions for poor people that would be likely to spark any revolt.
Looming issues: nuclear power and council tax reform
Two of the biggest issues that are likely to face the government in the next Parliament are the revision of council tax, and the looming question of whether to replace Britain's ageing nuclear power stations.
Dungeness nuclear power station will shut in 2008
Both are key issues for the Liberal Democrats, and the Conservatives have been campaigning hard on the council tax.
It is not apparent that Labour rebels would be eager to support the Opposition position on either of these issues - perhaps supporting higher council tax payments for richer homeowners, and accepting the need for a nuclear industry because of its role in creating jobs.
And the Liberal Democrats themselves are keen to play down the idea that they would work with Labour rebels.
Charles Kennedy told the BBC News website he would prefer to work with the Labour government and be consulted on key issues for the Lib Dems like the environment, pensions, and civil liberties.
And with the Tories pre-occupied with their own leadership battle, the government might be able to finesse these issues successfully.
It has already postponed council tax reform once, and Mr Blair has made it clear he does not want to proceed with nuclear energy until there is a public consensus on how to deal with the risks of disposing of nuclear waste.
Other issues which worry liberals, such as the treatment of asylum seekers and the increasing use of anti-social behaviour orders, have not provoked widespread Labour rebellions in the past.
On many key issues, such as tuition fees and foundation hospitals, there is relatively little the rebels can do, since the legislation has already been passed.
Charles Kennedy: reluctant to collaborate with Labour rebels
There may be a chance to review student tuition fees towards the end of the Parliament, and certainly any extension of them would have to be brought back for a vote.
Of course, if there were a re-run of the Iraq war in another country, the situation would be very different.
Both Tony Blair and Gordon Brown have suggested that in that situation, the government would seek a mandate in Parliament, just as it did before invading Iraq.
Such a move is unlikely, given that so many UK and US troops are already committed to Iraq - and the lack of political capital at home.
Blair v. Brown
Of course, many of the central battles of the next Parliament will revolve around the question of when - or if - Gordon Brown replaces Tony Blair as prime minister.
By and large, the Labour left is keen for Mr Blair to give way to Mr Brown as soon as possible - something that so far has been most clearly articulated by Clare Short.
There will no doubt be a series of shifting and tactical alliances, with some measures that are close to Mr Brown's heart (such as means testing and welfare reform) being opposed by the rebels, and others being supported.
One interesting test of this potential alliance will be the campaign for a yes vote on the European constitution, which is likely to start sooner rather than later (assuming the French do not throw the whole thing out on 29 May).
Mr Brown, one assumes, will be likely to back the prime minister's campaign in this regard, but many Labour rebels will not.