Mr Mills is due to face separate corruption charges in a Milan court next month. In both cases he is to be tried with Silvio Berlusconi, the media tycoon and former Italian Prime Minister, for whom he acted as a lawyer in the 1990s.

In the first trial, which opens on November 21, the charges involve tax evasion and money laundering arising from the acquisition of film rights by Signor Berlusconi’s Mediaset television empire in the 1990s.

Yesterday Judge Fabio Paparella, the Milan judge hearing that case, ruled that the two men should face a separate trial for perverting the course of justice, starting on March 13.

Mr Mills is accused by Milan prosecutors of accepting $600,000 (£315,500) from Signor Berlusconi in 1997 in exchange for giving false testimony on Signor Berlusconi’s behalf in two corruption cases — hence the additional charge of perverting justice. Both men deny all the allegations.

According to evidence gathered by the prosecutors, Mr Mills admitted in a letter to his accountant, Bob Drennan, that the $600,000 had come from “Mr B”, and was a “gift” to thank him for sparing Signor Berlusconi “a great deal of trouble”. This letter was unearthed by prosecutors investigating initial claims of fraud over film rights and now forms the basis for the latest charges laid against Mr Mills.

In the letter Mr Mills wrote: “I told no lies, but I turned some very tricky corners, to put it mildly.”

Mr Mills has since maintained that the letter merely outlined an “imaginary” situation, even though it contained the phrase “the brief relevant facts are these”. He said that he could prove that the payment had come not from Signor Berlusconi but from Diego Attanasio, a Naples shipping magnate who was another of his Italian clients.

Ms Jowell became drawn into the controversy when it was alleged that she and Mr Mills had used the $600,000 “gift” to pay off a mortgage that they had both signed. She was cleared however of breaching parliamentary standards and codes of conduct.

The couple have since separated.

Last night Mr Mills described the case as a waste of public money and said that it should never have brought. He predicted that he would be cleared. “I am completely innocent and the documents we have will irrefutably prove this,” he said.

Signor Berlusconi’s defence lawyers had argued unsuccessfully that Judge Paparella could not try both cases. Signor Berlusconi, 70, is Italy’s richest man. He has accused Milan prosecutors of being left-wing and of hounding him for political reasons.

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