The London Stock Exchange lost one its key executives on Monday as Martin Graham, head of markets, resigned amid a reorganisation of the top structure of the group.

The surprise move, confirmed by the LSE, comes as its new chief executive, Xavier Rolet, is preparing to take over from Dame Clara Furse.

Mr Graham will be replaced by the LSE group head of derivatives, Raffaele Jerusalmi, an Italian who was in charge of derivatives at Borsa Italiana, now part of the LSE group.