Sir Richard Branson is pondering the flotation of his mobile phone business Virgin Mobile to raise up to �700m, a newspaper reported.

Virgin Mobile, the smallest of the UK's five main mobile phone operators, had 22% growth subscriber numbers in the final three months of last year, impressing analysts at a time when growth opportunities were thought to be slender for mobile operators.

The flotation, on the London Stock Exchange, could see the mobile phone operator valued at around �700m and take place at some point in the next 12 months, the Daily Mirror said.

The launch would mark Sir Richard Branson's return to the stock market 14 years after he paid shareholders �260m to take his Virgin Group private again.

The paper said South African bank Investec would be appointed to float the company, along with JP Morgan Chase, Virgin Mobile's existing bankers.

Investec's involvement is seen as significant because Virgin Mobile is preparing a big marketing push in South Africa, the paper said.

Virgin Mobile had 1.4 million customers at the end of last year, after signing up 264,359 new subscribers signed up between September and December.

The firm does not have its own network but leases bandwidth from number four operator One2One.