Orange has announced that Tom Alexander, the former chief executive at Virgin Mobile, will take over as leader of Britain’s third-biggest mobile operator in the company's third management shake-up in six months.

Mr Alexander, who left Virgin Mobile in 2006 when it was taken over by NTL/Telewest, will assume the chief executive role at Orange from Bernard Ghillebaert who held the position since 2004.

Mr Alexander will report to Olaf Swantee, senior executive vice president personal communication services UK & EMEA for the Orange Group, and will join the company in December 2007.

Mr Ghillebaert will take a role in Mr Swantee's executive management team.

Mr Alexander quit Virgin Mobile last year, with a £6 million payout, after it merged with NTL/Telewest, the cable group, to become Virgin Media.

He is believed to have felt reluctant to stay on in the mobile operations, which he built from scratch with the backing of Sir Richard Branson, once they had lost their independence.

He said at the time that he wanted to concentrate more on racing, his hobby, and to spend more time with his young family in Somerset.

Commenting on Mr Ghillebaert, Mr Swantee said: "Bernard has made an essential and lasting contribution to Orange in the UK over the last three years and I look forward to him replicating this success in his new group level role.

"When he came to the UK in 2004, Orange was a mobile phone company. Over the last three years, while ensuring stability for the business, Bernard has also laid the foundations for the future of Orange as a total communications company.

"I now look forward to seeing Tom build on those foundations."

Today's move follows the departure of Sanjiv Ahuja from his job as head of Orange’s global mobile operations in April. Last month, Eric Abensur, head of Orange UK’s broadband operations, left the business.

The UK’s mobile market is one of the world’s most fierce and the profitability of Orange UK, the UK’s third biggest player with a 21.5 per cent market share by revenue, is falling as it struggles to compete with rivals Vodafone and O2.

In the six months to the end of June, Orange reported operating profits of €712 million, down 8.6 per cent against the same period last year.

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