Little has over 20 years' experience in the financial technology industry.

He was co-founder and managing director of Braid Systems, a provider of EAI and secure messaging technology that was acquired by Nasdaq-listed Mercator in 1999.

Since then Little had held a number of roles including interim CEO at middleware vendor Dovetail Systems and chairman of software house Singularity.

He has also been an active investor and board member of various firms including UK treasury, securities and derivatives software vendor City Networks, Whittaker & Garnier - a provider of CRM software to the hedge fund industry - and wealth management software firm Investmaster.

In his new role Little will be based in Citadel's London headquarters and his initial focus will be on strengthening the vendor's position across Europe and the US.

Commenting on the appointment, John Dallas, chairman, Citadel, says: "Peter is a veteran of the financial services industry. As such, he is the ideal candidate to drive our growth strategy."