The Transport Secretary will continue the Government's fightback over the High Speed 2 (HS2) rail line today.
He will unveil - yet another - business case for the controversial £42 billion line which will link London with Birmingham, Manchester and Leeds.
I understand the new cost-benefit ratio - which has been calculated by those who support the project - will be around 1:2.
It means that ministers will claim that £2 of benefits will be created for every £1 the Government spends on building the new line.
The cost-benefit ratio is politically necessary to justify the huge costs of the line to those Conservative and Labour MPs who are becoming increasingly sceptical of the plans for HS2.
The Secretary of State in charge of the project, Patrick McLoughlin, will also criticise the increasingly cool support from Labour for the project.
He will say of Labour's position:
You can’t say one day you back better infrastructure only the next threaten to stop it being built.
You can’t go on claiming to want one nation if you won’t back the things that will bring it together. You can’t play politics with our prosperity.
Mr McLoughlin also singles out shadow chancellor Ed Balls for criticism.
Mr Balls has recently stated that Labour will not support a "blank cheque" for the project, amid concerns the price could rise beyond the £50 billion mark.
The Transport Secretary will say:
And to those who say there’s no blank cheque, I just say: that’s obvious. Did anyone ever claim there was?
Britain has shown it can build great infrastructure like HS1 or the Olympics on time and on budget.
Later this week, MPs will vote on a "Paving Bill" which authorises the release of money for the project before the full legislation is debated in Spring 2014.
And on Friday, ministers will give further details of a study to extend the high speed line beyond the North of England to Scotland.