America is on course to stage the world’s first billion-dollar election with candidates already raising in excess of $100 million, fully 19 months before voters choose which one will be the next US president.

Hillary Clinton, as expected, has so far been the biggest earner by generating $26 million (£13.2 million) in the first quarter of this year – on top of $10 million left over from her Senate election in November.

The figure, released by the Democratic front-runner’s campaign in a blaze of publicity on Sunday afternoon, is a record for this stage of the race and almost matches the $29 million raised by all candidates combined four years ago.

The Republicans are not far behind. Mitt Romney, the former Massachusetts Governor who is trailing badly in the opinion polls, reported that he raised $23 million for his presidential campaign during the first three months of the year.

Rudy Giuliani, the former New York Mayor and Republican front-runner, said that his donations totalled $15 million, including $10 million raised in March alone. John McCain, another leading Republican candidate, lags in third place with $12.5 million in contributions.

The “money primary” is seen as a crucial test of a candidate’s viability and Mr McCain’s campaign manager, Terry Nel-son, expressed disappointment. “We had hoped to do better in first quarter fundraising,” he said. “We are already in the process of taking the necessary steps to ensure fundraising success moving forward.”

Despite the huge quantities of cash amassed by Mrs Clinton, she has not delivered the knock-out blow that some of her supporters had hoped for. Barack Obama, her chief rival for the Democratic nomination, has not released figures but his and Mrs Clinton’s aides are predicting that he has come close to her total by raising upwards of $20 million.

Mrs Clinton’s lead could appear even smaller later this month when the Federal Elections Commission publishes a detailed breakdown. In the figures released at the weekend, Mrs Clinton did not say how much of her money was reserved for the general election, as opposed to the primary contests to pick the Democrat nominee.

Many of her events required a contribution of $4,600 for VIP-access. That is the legal maximum individual donation, with the money evenly divided between the two phases of the election.

Mr Obama usually sought maximum donations of $2,300, which means that the bulk of his take this quarter will be available for the primary campaign. Figures also suggest that his donor base is substantially larger, taking contributions from 83,531 people, compared with approximately 50,000 who gave money to Mrs Clinton.

Jan Baran, a campaign finance lawyer, said: “At this stage, the campaigns only tell you what they want. We don’t know, for instance, how much of Clinton’s money is for the primary campaign. Nor do we know how much she has spent.”

Some heavily staffed campaigns are said to be costing up to $2 million a week. Mr Romney has already spent on televi-sion advertising campaigns and his $23 million total yesterday included a $2.35 million loan from his personal fortune, which aides said was needed as “seed money”.

In a sign of how the dash for cash has become more frantic than ever, John Edwards – another top-tier Democratic candidate – has raised almost twice as much as he did four years ago when he led the field for first-quarter fundraising. But his total of $14 million is little better than average this time around.

In 2004 the presidential election cost $769.5 million. Federal officials have already predicted that it will top $1 billion next year.

Britain’s general election in 2005 cost £35 million. Mr Baran said that the two systems are not comparable because Britain bans TV advertising and has a shorter election. He disclosed that Michael Spencer, the Tory treasurer, had visited him in Washington last week to learn about US fundraising techniques, he said. “He was very interested in how we do things, but I told him it was like going to the zoo to ask how they breed mammals when all he does is raise fish.”

Asked if 2008 would be a billion-dollar election, Mr Baran replied: “Of course it will! What’s a billion dollars? It doesn’t go that far these days.”

Times Recommends

• Should Knox’s trial even have reached the courtroom?
• 'Was it real?' The US bailout nightmare
• Iranian opposition plays the long game