Chancellor Alistair Darling is to make a full statement on Bradford & Bingley before the markets open on Monday morning.
Top-level talks over ailing lender Bradford & Bingley are continuing amid reports the bank faces imminent nationalisation.
B&B is in discussions with the so-called Tripartite Authority - the Treasury, Financial Services Authority and the Bank of England - over the potential bail-out as the bank is buffeted by the credit crunch.
The Treasury would only say that discussions were "ongoing", although an announcement could come later or early Monday morning before the Stock Exchange opens.
The BBC, which reported the nationalisation late on Saturday night, said B&B will be sold on almost immediately to another bank or banks.
However it was clear that the bank was set to become the latest victim of the global credit crunch which has paralysed the world financial system.
According to the BBC, the Government will nationalise B&B using the special legislation passed to take Northern Rock into public ownership earlier this year.
Treasury Chief Secretary Yvette Cooper told BBC1's Politics Show: "Negotiations are still under way at the moment."
"There have been concerns for some time about the Bradford and Bingley business model and the position they have got themselves into.
"We have been very clear that the priority is to make sure that depositors, that ordinary savers will be properly protected, but also that we can support the stability of the banking system as a whole."
