Surprise awaiting in Budget
Rarely can a Budget box have contained so few surprises - though the chancellor hopes that at least one remains - the extent to which he is willing to reform the tax system.
George Osborne has decided to take the political risk of cutting taxes on the earnings of the rich as well as those on more modest incomes.
He will insist that it can all be paid for by increasing the cost to the rich of buying their homes and capping the tax relief they can use to shield their income from the Revenue.
So, the 50p top tax rate will be cut - though not straight away and not all at once.
There'll also be an increase in the amount you can earn before paying any tax at all, to more than £9,000 from April next year.
Planned cuts to child benefit will be revised to affect fewer families.
The billions all this will cost look set to be paid for by higher stamp duty on the sale of homes worth £2m or more, curbs on what is now legal tax avoidance and, we're told, a cut in public spending beyond those already unveiled.
What that cut is remains - for a few hours longer - one of the few budget secrets.