THE Home Office blatantly jeopardised an investigation designed to bring Tessa Jowell’s husband David Mills to trial, according to Italian prosecution documents seen by The Times.

As doubts persisted over the future of the Culture Secretary, the prosecutors claimed that the Home Office had harmed their inquiry and a move to extradite Mr Mills by revealing “extremely sensitive information” to the Berlusconi Government — the targets of the probe.

In a furious letter to a senior Home Office official, the prosecutors alleged that by passing to the Italian Justice Ministry written evidence relating to the proposed extradition the British Government had “spread reserved information among a large number of officers and people . . . the damage to investigative secrecy is blatant,” they wrote.

By informing the Justice Ministry, the Home Office had directly involved the Berlusconi administration — the very people who would fear damage from Mr Mills’s extradition. Simultaneously, the Serious Fraud Office suddenly stopped dealing directly with the prosecutors in Milan, instead sending evidence in “unsealed packages” via the Berlusconi Government, it was claimed in a letter from the prosecutors seen by The Times and the Italian newspaper La Stampa.

However, the Home Office insisted last night that all correct procedures were followed and no minister was involved in any of the decisions.

Mr Mills, a tax avoidance lawyer, has been accused of protecting Signor Berlusconi in two corruption trials in 1997 and 1998 and receiving £350,000 as a “bribe”. He denies wrongdoing.

Downing Street yesterday continued to offer guarded support to Ms Jowell, while the review by Sir Gus O’Donnell, the Cabinet Secretary, into the financial affairs of the couple appeared to have developed into a full-scale inquiry. No 10 said that the “facts have to be established” as Sir Gus sought further clarifications from Ms Jowell to see whether she had complied with the ministerial code of conduct. David Cameron, the Tory leader, said that she would have to quit if Sir Gus found against her.

Friends of Ms Jowell were privately confident that Sir Gus would conclude that she had not broken the code. She is expected to issue a statement when Sir Gus announces his findings, probably tomorrow.

The Italian prosecutors’ criticism of the Home Office is clear in a letter, seen by The Times, from Fabio de Pasquale, the chief Milan prosecutor, to Richard Bradley at the Home Office. In it Signor de Pasquale says that the Home Office’s decision to deal with the Italian Government “appears unjustified and systematically jeopardises the investigative secrecy that should cover all the evidence transmitted to the British authorities”.

A Home Office spokesman said usual procedures had been followed. “Any information about extraditions before July 28, 2005, when the European arrest warrant was introduced, had to be conducted through diplomatic channels rather than direct between UK and Italian prosecuting authorities.”

In a fresh embarrassment last night to Ms Jowell, details of a meeting between her husband and a financial consultant, Paul Calkin, were leaked. They show that the couple appear to be joint clients of Mr Calkin. This could contradict an earlier statement by Mr Mills that: “Our finances are totally separate.”

At the meeting on September 3, 2004, not attended by Ms Jowell, Mr Mills apparently told Mr Calkin that the £350,000 sum had come from a “gentleman called Diego”. This appeared to be a reference to Diego Attanasio, a shipping magnate — something Mr Mills only revealed to prosecutors in November 2004. Two months previously he had told prosecutors that the money had come from a friend of Silvio Berlusconi.

The note also details Ms Jowell’s ministerial salary and savings, and suggests that Mr Mills told Mr Calkin that she would stay in politics for two more parliamentary terms before moving to the Lords.

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