* CEO apologises in full-page newspaper advertisments
* Accused in media of helping clients to evade tax
* Has admitted failings in compliance and controls (Writes through, adds quotes, background)
By Paul Sandle and Steve Slater
LONDON, Feb 15 (Reuters) - HSBC apologised tocustomers and investors on Sunday for past practices at itsSwiss private bank after allegations that it helped hundreds ofclients to dodge taxes.
Europe's largest bank said in full-page advertisements inBritish newspapers that recent media coverage that focused onthe Swiss operation and financial affairs of some of its clientshad been a painful experience and that standards in place today"were not universally in place" in the past.
"We therefore offer our sincerest apologies," theadvertisment said. It is addressed to customers, shareholdersand colleagues and is signed by Chief Executive Stuart Gulliver.
Most of the message echoes an email sent to staff on Friday,when Gulliver said that the bank had sometimes failed to live upto the standards expected of it.
HSBC has admitted failings in compliance and controls in itsSwiss private bank after the media allegations that it may haveenabled clients to conceal millions of dollars of assets, thoughGulliver said that many people alleged to have been customershad long since left and some never were clients.
The disclosures have sparked a political row in Britain overpractices at HSBC and whether tax authorities had done enough topursue possible wrongdoers.
Britain's Treasury Committee has called the bank's chairmanand chief executive to give evidence on the matter on Feb. 25,according to a memo seen by Reuters on Friday.
'EXPLANATION NEEDED'
Business minister Vince Cable said that he is seekingreassurance that such practices have been consigned to history.
"It's one thing to say that these things happened 10 yearsago, and we do need a proper explanation of that, but what isabsolutely essential is that the practices are not continuing,"Cable told the Murnaghan show on Sky News, adding that he hadwritten to HSBC.
Cable also said that the tax authorities need to take afirmer approach.
"The treatment of small people and poor people is verysevere, but the big fish -- the companies and rich individuals-- are not being treated as seriously," Cable said. "That iswrong and it must change."
The revelations have proved embarrassing for a governmentthat included HSBC's former boss Stephen Green as minister fortrade from 2011 to 2013.
"(Green) hasn't yet spoken on his role in the matter and Iwould certainly like him to do so," Cable said on Sunday.
Green stepped down as chairman of financial services lobbygroup TheCityUK on Saturday.
The bank said that the vast majority of the 140 people namedin reports as customers of its Swiss bank had left and that ithas since established much tighter controls on who it accepts ascustomers.
"We have absolutely no appetite to do business with clientswho are evading their taxes or who fail to meet our financialcrime compliance standards," Gulliver said.
Opposition Labour leader Ed Miliband said on Saturday thathe would implement a "root and branch reform" of taxauthorities' approach to avoidance if Labour wins the nextelection. (Additional reporting by Sinead Cruise; Editing by DavidGoodman)
HSBC Holdings (HSBA)