When Nomura bought Lehman Brothers’ European business a year ago Mark Butterfield, its head of technology for Europe, the Middle East and Africa, had just a few hours to decide if it was feasible to plug Lehman’s systems into Nomura’s infrastructure.

Three months after the deal, the former Lehman equities arm was back in business and one year on Nomura International is the top trader on the London Stock Exchange, a position formerly held by Lehman.