LONDON (Reuters) - Britain's Lloyds Banking Group (LLOY.L) will probably sell 30 to 50 percent of its stake in the 631 bank branches being rebranded as TSB when the new entity floats on the stock market in 2014, a newspaper reported.

TSB's Chief Executive Peter Pester told Britain's Sunday Telegraph that TSB will begin its roadshow relatively soon, with the listing planned for the middle of next year.

The share sale will also include a retail offering, Pester said.

Lloyds was ordered to sell the branches by European regulators as a penalty for receiving a 20-billion-pound ($32 billion) government bailout in the 2008 financial crisis.

Pester also said that in the ten weeks since TSB launched a new advertising campaign, customers had been signing up for current accounts twice as quickly as the group had estimated.

(Reporting By Christine Murray; Editing by Ruth Pitchford)