LONDON (Reuters) -Around 3,000 people at Britain's Lloyds Banking Group, judged to be among the bottom 5%, will find themselves considered for possible dismissal, a source familiar with the matter told Reuters, as CEO Charlie Nunn pursues cost cuts.

Lloyds expects about half that number will lose their jobs unless their work improves, the source said, declining to be named, while adding there was no fixed target for layoffs from its 63,000-strong workforce.

Along with other banks in Britain, Lloyds has reduced its high street presence, saying in January it would shut 136 branches as more customers take up digital banking, although it said that would not directly result in job cuts.

Economic uncertainty has also made workers cautious about changing jobs. Lloyds employees have been leaving at an annual rate of 5% each year compared to an average of closer to 15% historically, according to the Financial Times newspaper, which first disclosed the performance shake-up.

U.S. banks have typically been the most aggressive in sacking what they regard as the least productive of their workforce, especially when profitability dwindles.

A Lloyds spokesperson told Reuters in an emailed statement that it was transforming its business and "striving to embed a high-performance culture".

"We know change can be uncomfortable, but we are excited about the opportunities ahead as we propel forward to achieve our growth ambitions and deliver exceptional customer experiences," the spokesperson said.

The Financial Times reported managers would place underperformers on "structured support" plans and that they would be dismissed if that did not lead to improved performance.