RBS shareholders to vote on bank's pounds 20bn bail-out.
RBS, one of the worst hit by the banking turmoil, has called a general meeting in Edinburgh to approve the rescue.
The bank is boosting its finances by offering pounds 15bn in new ordinary shares, with the Government promising to buy any remaining.
But because RBS's shares are trading well below the 65.5p offer price, investors are likely to snub them.
This leaves the taxpayer - currently sitting on a paper loss of about pounds 5bn on the newshares - with a potential 58% stake.
On top of the pounds 15bn share issue, RBS shareholders will vote to approve issuing pounds 5bn in preference shares to the Government, which the bank will buy back over time.
RBS cannot pay any dividends to shareholders on its ordinary shares while any of the preference shares are outstanding.
The drastic fundraising moves come on top of a pounds 12bn rights issue by RBS earlier this year before the financial crisis worsened.
Last year's acquisition of Dutch bank ABN Amro had already stretched RBS, and the subsequent turmoil and bail-out cost chief executive Sir Fred Goodwin his job.
The bank, which owns NatWest, wrote off pounds 5.9bn in credit crunch losses in the first half of this year and - for the first time in its history as a public company - is likely to make a full-year loss during 2008.
Lloyds TSB shareholders yesterday voted 95.98% in favour of the proposed takeover of ailing rival HBOS. They also backed plans to raise pounds 5.5bn by issuing of new shares and special preference shares.