RUPERT Soames has started to stamp his authority on Serco with a cull of international management which is likely to see around 50 people leave.

The former Aggreko chief executive was brought into Serco at the start of May and immediately announced a strategic review of the whole business. That process is likely to last around nine months with the company suggesting the management changes are not directly related to the review.

Serco announced yesterday the Hong Kong office in its Africa, Middle East, Asia and Australasia division will be closed.

David Campbell, chief executive of that arm, will retire at the end of the year although Serco pointed out he had already extended his planned retirement date.

The move to close Hong Kong effectively wipes out a layer of middle management with the Middle East business, headed by David Greer, and the Australia, New Zealand and Asia arm, led by Mark Irwin, now reporting directly to Mr Soames and chief operating officer Ed Casey. Mr Soames said: "This change will simplify the management structure, reduce cost, and give our important growth markets in the Middle East and Australia greater visibility."

Separately the company announced it was planning to split from its rail joint venture partner Abellio. The businesses have run the Northern Rail service for more than a decade but a new tender process is to start in early 2016.

Serco said: "Given the individual strengths of each company's rail credentials, Serco and Abellio have agreed that they will pursue separate paths in respect of the new Northern Rail franchise."

Serco recently won the contract to run the Caledonian Sleeper and indicated it is looking at possible bids to run other rail franchises in the UK and around the world. It said it is "evaluating options" for Northern Rail and the Transpennine Express, which is also up for tender in 2016.

Mr Soames said: "We evaluate each opportunity on individual merit, and focus on those where we can have a transformational impact."

Prior to Mr Soames coming in Serco had lost a multi-million pound contract for tagging offenders in the UK and experienced problems in Australia.