The Russian-Israeli businessman Arkady Gaydamak has lost a High Court claim against diamond tycoon Lev Leviev over a deal to export gems from Angola.

Mr Leviev had denied signing an agreement with Mr Gaydamak in December 2001 potentially worth hundreds of millions of pounds.

But Mr Justice Vos agreed that the two men had made a pact and that Mr Leviev had deposited the only signed copy of it for safekeeping with the Chief Rabbi of Russia Berel Lazar.

However, the judge also upheld a settlement between the two businessmen to drop all legal claims, which was brokered by a senior minister in the Angolan government in Luanda last year.

Mr Gaydamak had argued that the settlement was invalid because he had signed it only after having been led to believe by Angola’s Minister of State General Kopelipa that Mr Leviev would pay him compensation.

But the judge pointed out that the settlement did not contain any financial promise, concluding that while General Kopelipa may have offered to use his influence with Mr Leviev to ask for money for Mr Gaydamak, that did not amount to an assurance Mr Leviev would pay it.

Mr Justice Vos said that there had been “no satisfactory explanation” why Rabbi Lazar did not come to London to give evidence or for “his unwillingness to give evidence by video link as many other witnesses did”.

In a witness statement, Rabbi Lazar said that he had lost the document.

Mr Leviev claimed that the document had related not to a business deal but a pledge by Mr Gaydamak to give charitable donations to the Russian Jewish community – a version of events which the judge described as “manufactured”.

Mr Gaydamak plans to appeal.