He replaces Chris Tupker, who has held the job since July 2006. Tupker announced in September his intention to step down. He was then aged 65. LCH.Clearnet had hoped to find a replacement by the end of December.

Aigrain had been chief executive of Swiss Re, the reinsurance company, for three years until he resigned in February 2009 after the company made a record full year loss for 2008 of Sfr860m. Swiss Re was then forced to take a Sfr3bn cash injection from Berkshire Hathaway. The loss was caused by financial investments such as credit default swaps that suffered Sfr5.9bn of writedowns that year – a business with which Aigrain was closely associated.

Aigrain joined Swiss Re in 2001 as head of financial services, New York. Before that he spent 19 years at JP Morgan Chase in New York, London and Paris.

At LCH.Clearnet Aigrain will be based in London. The clearing house declined to say how many days he would work but told FOW: “The role is non-executive, however, he is committed to the role and will work as required to achieve the company’s goals.”

Tupker said: “Jacques’ wealth of experience in the financial sector will be a great asset to the company and the markets it serves as LCH.Clearnet continues to work with its users to develop its leading position in clearing markets internationally.

“My four years at LCH.Clearnet have been both exciting and challenging. Last year’s capital restructuring was the final step in a three year programme to align ownership and usership more closely and the group is now positioned well for the future.”

Tupker helped steer LCH.Clearnet through difficult waters in the last 18 months as it first planned to merge with Depository Trust & Clearing Corp of the US, then found its shareholders opposed the deal.

Many of the leading dealers that also hold stakes in LCH.Clearnet then backed a rival bid by Icap, the interdealer broker. But LCH.Clearnet’s management saw off that challenge and ended up winning overwhelming support among shareholders for a plan to cut fees, redeem some of its capital and realign shareholdings more closely with the structure of its customer base.

That plan was made public and pushed through a shareholder vote shortly after Tupker announced on September 22 that he would resign.

Before joining LCH.Clearnet Tupker, a Canadian, was chairman of Euroclear – until last year LCH.Clearnet’s biggest shareholder. Before that he was chief operating officer of ABN Amro’s investment bank.