President Obama, having campaigned on a promise to end the culture of cronyism, seems poised to appoint one of his biggest campaign fundraisers as the next American ambassador in London.

Although the nomination of Louis Susman has not yet been signed off by the White House and the US State Department, the 71-year-old investment banker's name has been strongly linked with the post in recent days.

Mr Susman is a long-time Democratic donor who spotted the potential of his fellow Chicagoan almost five years ago and has since acted as a so-called “bundler”, by drawing in multiple campaign contributions up to the legal maximum of $4,600 from his network of wealthy Wall Street contacts.

He raised at least $500,000 for Mr Obama's election and inauguration funds, while also contributing more than $100,000 of his own money to Democratic Party causes last year. Citigroup, the bank from which he resigned as vice-chairman of the global markets division this month, is seeking a federal rescue worth $45 billion from the new Administration.

Around a third of plum postings abroad have traditionally been awarded to friends, fundraisers and donors who have no diplomatic training. They are said to have included an ambassador to France who did not speak French and one to Switzerland who believed that part of the country spoke Romanian. Robert Tuttle, the current holder of the official title Ambassador to the Court of St James's, was a Beverly Hills car-dealer who raised at least $100,000 for George Bush's election campaign.

Mr Obama used a press conference this year to emphasise that while he wanted to appoint qualified career diplomats for most ambassadorships, “it would be disingenuous” to expect a total ban on political nominations.

Ronald Neumann, who heads the American Academy of Diplomacy, has written to the President asking him to limit such appointments to 10 per cent of the 200 posts available overseas.

Yesterday he greeted reports of Mr Susman's nomination cautiously. “It does not tell me that anything much has changed,” he said. “But before we start getting into too much of a twist about it we must look at whether other big contributors with no obvious qualifications secure senior posts.”

A senior Democratic figure was disdainful: “As far as I know this man has no knowledge whatsoever of foreign policy. Am I missing something here?”

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