HSBC's legal troubles are growing. The British tax authorities said Friday that they were looking into a list of HSBC clients with bank accounts in the tax haven of Jersey.

Her Majesty's Revenue and Customs, Britain's tax authority, is investigating more than 4,000 accounts in Jersey that belong to British clients after receiving details from a whistle-blower. The list includes a drug dealer and a man convicted of possessing more than 300 weapons at his home in the south of England, The Daily Telegraph reported.

We have received the data and we are studying it,'' a tax authority spokesman wrote in an emailed statement. ''Clamping down on those who try to cheat the system through evading taxes and over-claiming benefits is a top priority for us, and we value the information we receive from the public and business community.''

Jersey, the largest island in the English Channel, is a British dependency with its own tax system.

HSBC, Britain's largest bank, is already part of an investigation into money laundering. The bank said earlier this month that it set aside an additional $800 million to cover potential fines from the money-laundering case, bringing the total to $1.5 billion. The bank, which is negotiating a settlement with the American authorities, added that the actual fine could be even bigger.

In addition, HSBC, like other major British banks, has had to set aside cash to reimburse British customers who were sold inappropriate insurance products.

HSBC said Friday in a statement that the bank was ''investigating the reports of an alleged loss of certain client data in Jersey as a matter of urgency.'' HSBC said it had not yet been informed of any investigation but would fully cooperate with the authorities. ''HSBC remains fully committed to adoption of the highest global standards, including the procedures for the acceptance of clients,'' it said.

Prime Minister David Cameron of Britain has made the crackdown on tax evaders a priority for a government under pressure to increase revenue and reduce the budget deficit.

Following the financial crisis, banks face greater scrutiny from the authorities worldwide about how they conduct their business.

HSBC's management was forced to apologize publicly for the problems that weighed on its earnings and share price as recently as Monday and has already started to change its compliance and oversight functions.

The money laundering scandal began when the Senate Permanent Subcommittee on Investigations accused HSBC of allowing some of its executives to let illegal behaviour go unchecked for nine years, until 2010. In one example, the bank provided financing to Al Rajhi Bank of Saudi Arabia, even though some of the bank's owners were linked to the financing of terrorism, according to the Senate report.

HSBC clients are also on another list that was in the spotlight this month. Kostas Vaxevanis, editor of the investigative magazine Hot Doc, was acquitted last week on charges of breaching privacy laws when he published a list of more than 2,000 Greeks believed to hold accounts at a Geneva branch of HSBC. The list was given to the Greek authorities two years ago by Christine Lagarde, then the French finance minister and now managing director of the International Monetary Fund, to help the government in Athens investigate evasion.