By Nick Assinder
Political correspondent, BBC News website
Culture Secretary Tessa Jowell is playing for high stakes as she attempts to face down rebels threatening to destroy her plans to site Britain's first super-casino in Manchester.
A combination of 100 MPs, the opposition parties and bishops may succeed in defeating the proposal in either the Commons or the Lords after a powerful campaign for a government re-think on the issue.
Ms Jowell has a lot riding on the casino votes
The effect would be to shred Ms Jowell's plans, dismay Manchester, boost Blackpool's hopes of a change in its favour and land the government with another major embarrassment.
It could deny other towns the 16 smaller casinos included in the government's all-or-nothing package.
And it is widely predicted it would finally kill off any lingering hopes the minister may have of keeping a job under a Gordon Brown premiership.
'No Plan B'
Just hours before the crunch votes the outcome was still too close to call, and the whips were engaging in all their tactics of giving some MPs permission to miss the vote while arm-twisting, threatening and cajoling others to persuade them to fall into line.
The high stakes game saw Ms Jowell accused of offering a multi-million pound regeneration package to Blackpool in an attempt to buy off rebels.
She denied that, telling the Financial Times : "We are not talking about buying off a rebellion. This is very much in response to specific representations by a very large number of MPs".
Manchester would be dismayed at losing casino
But she also admitted there was no "plan B" in the event of defeat - also seen as a high-risk strategy aimed at spooking rebels into backing the government by suggesting they might kill off the entire package for the foreseeable future.
She is also arguing that, having asked the independent Casino Advisory Panel to recommend where the casinos were sited, it was her duty to implement its findings.
Win the day
Some of the arguments appeared to be working with signs that some of the rebels were not prepared to join with the opposition to defeat the government.
Many potential Labour rebels were angry at what they saw as an opportunistic U-turn on the issue by David Cameron, designed purely to embarrass the government.
Similarly it would be highly unusual for peers to throw out a piece of government legislation of this particular type - a statutory instrument which allows measures to be introduced by ministers without parliament passing a new act.
And, despite all the rumblings, both the government and whips appeared relatively relaxed and were claiming they were confident they would win the day.
However, with the prime minister's authority rapidly evaporating and MPs apparently getting a taste for rebellion, the outcome still cannot be predicted with any certainty.
And Ms Jowell was being reminded of the oldest saying about casino gambling - whatever the stakes, the House always wins.