A takeaway curry and then biscuits to seal the deal

As the chicken korma, pilau rice and poppadoms were passed around the tables, the Chancellor and his officials geared up for one last push to nail down the detail of today's £500 billion rescue.

Alistair Darling, leading the negotiations in his sparse, modernist second-floor office, then embarked on a prolonged session of horse-trading that only ended when he went to bed at 1.45am. The crucible of the deal was the Chancellor's boardroom style table, with Treasury experts hammering out issues such as guarantees and preferred share types with some of the biggest beasts in the City's banking world.

Sir Fred Goodwin, the chief executive of RBS, was one of the few CEOs present, with some other banks allowing their senior finance officers to do the hard bargaining.

Tea and biscuits were brought in around 1am as the biggest issues were finally thrashed out on a deal that the Treasury insists had been planned for weeks.

Whitehall sources said that most of the architecture of the plan was already drafted but until the past week it had been very difficult to get the necessary agreement from the banks.

On the Treasury side, Mr Darling felt he had a formidable team. He was accompanied by new city minister Paul Myners, a poacher turned gamekeeper familiar with a hard-headed businessman's instincts as a former chairman of Marks and Spencer, as well as his youthful team of economists and civil servants. Nick Macpherson, the 49-year-old permanent secretary, John Kingman, the 38-year-old managing director of public services and growth and Tom Scholar, the 39-year-old managing director of international and finance, all stayed up through the night.

When he was Chancellor, the Prime Minister built up the current Treasury team and Mr Scholar spent a brief spell at No 10 as the Prime Minister's chief of staff before returning to the Treasury. Gordon Brown was kept informed by phone throughout and was finally consulted as the Chancellor signed off the deal at 5am.

It was made clear that although there would be no legal "strings" attached to the rescue plan, the banks would be expected to start lending to each other again quickly and to make life easier for businesses and families.

After the bankers left the Treasury in the small hours, Mr Darling woke up at 4.30am and took just half an hour to finalise the plans.