(Adds Co-op Bank response, details)
LONDON, April 30 (Reuters) - An independent review of the problems which led to a 1.5 billion pound ($2.5 billion) funding gap at Britain's Co-operative Bank has concluded the roots of its problems lay in its 2009 takeover of the Britannia Building Society.
The report by Christopher Kelly, which was commissioned by the Co-op last year, said the bank's demise reflected a "sorry story of failings in management and governance on many levels".
The bank's future came under threat last year when the capital shortfall was exposed, before a rescue saw it fall under the control of shareholders including U.S. hedge funds.
"The roots of the shortfall lie in a merger between the bank and the Britannia Building Society which should probably never have happened. Both organisations had problems. Bringing them together exacerbated those problems," Kelly said in the report, which was published on Wednesday.
The report said Co-op Bank's board had failed in its oversight of management and to properly manage capital and risk.
Co-op Bank said on Wednesday it broadly accepted the report's findings.
"On behalf of the bank I would like to apologise for these past failings," said Co-op Bank Chief Executive Niall Booker.
"The board will consider the implications of today's report and, bearing in mind the various external investigations into the same past events which are still ongoing, consider what action it should take, after taking appropriate professional advice," he added.
($1 = 0.5936 British Pounds) (Reporting by Matt Scuffham, Editing by Paul Sandle)