Brown sat silently as Judge Geoffrey Rivlin, QC, addressed Court 1 at Southwark Crown Court in Central London.

“These are two very serious offences. With regards to the charge of obtaining a false passport, this was a very direct and pointed flouting of a direct court order,” he said. With regard to the second count of perjury this was very deliberate and well thought through.”

Judge Revlin added that Brown’s donation to the Lib Dems was not a factor while sentencing. “I do not take into account the well publicised donation you made to a major political party,” he said.

Brown gave the Liberal Democrats the donation early last year after contacting key figures, including Mr Kennedy and Lord Razzall, then the party’s leader and treasurer.

The money was paid through his bank account held in the name of his British company 5th Avenue Partners. He was banned by law from making political donations as an individual because he is not on the British electoral roll.

HSBC, Brown’s bank, began a civil action against the businessman and 5th Avenue Partners last year. As part of those proceedings, Brown swore an affidavit stating that millions of pounds from HSBC accounts had been used as collateral for trading and generated $16.5 million (£8.9 million) profits.

By December the bank said that statements in the affidavit were false. The bank suspected that no such trading had ever taken place. Although he had surrendered his passport, Brown obtained a new one by pretending that the document had been destroyed in a Spanish washing machine.

Brown returned home to Majorca but the CPS obtained a European arrest warrant.

Detectives descended on the villa he shares with his wife Sharon in Esporlas, on the island’s west coast, and arrested him as he celebrated his 40th birthday. He was brought back to Britain in May, accompanied by three City of London detectives. As the aircraft landed, he told The Times: “This dispute is just a disagreement between a bank, the investors and me.”

In July, Brown pleaded guilty to one charge of perjury in respect of the affidavit. He admitted making “an untrue statement” to the Passport Office. Another 30 charges brought by HSBC will remain on file.

Nicholas Purnell, QC, for the defence, said yesterday that Brown had panicked — partly because he wanted to return home to adopt a child from a former Soviet state.

“My client’s whole world had been turned upside down. His life has been utterly transformed from the successful bonds trader he was in October 2005,” he said.

The bearded multimillionaire, who owns two properties in Majorca, as well as a home in Mayfair, Central London, has had his assets frozen.

Detectives have also taken charge of two cars, a yacht and his private jet. He was jailed for 18 months for perjury and six months consecutive for obtaining the passport. The 159 days he has spent in custody will be deducted from his sentence.

He has been in trouble with the law before, the court was told. The Times revealed last year that he was placed on probation in Florida for passing a worthless cheque to a lawyer.

Explore Law

• Columnists

• Law Panel

• Law Reports

• Student Law

Times Recommends

• BGC 'set aside £40m to lure Tullett brokers'
• Legal aid review to ensure value
• Fears as 21 magistrates' courts face closure