REVENUE & CUSTOMS refused to confirm this weekend that it has a hit list of 30,000 people using credit or debit cards connected to offshore accounts who may be using those accounts to evade tax, writes William Kay.

It is understood, however, to have instructed UK credit-card companies to surrender records of potential offenders, according to advisers involved in the inquiry.

A Revenue spokesman said: “It is known that there are a variety of ways in which people try to hide money offshore. We will continue to ensure that everyone who is liable pays the correct tax, and hiding money offshore is not acceptable.

“We cannot comment on which areas we are targeting because that would warn off the people we are trying to identify.”

The Revenue announced the appointment of its first-ever director of criminal investigations last week. Roy Clark, a former head of Crimestoppers and deputy assistant commissioner of the Metropolitan Police, is expected to take up the post within the next few months.

Mike Eland, director- general of enforcement and compliance, said: “Roy has considerable experience of investigation work, which makes him very well qualified to lead a team of 2,000 investigators tackling fiscal fraud and smuggling, which costs the UK billions of pounds a year in lost revenue.”

Gordon Brown, the chancellor, has committed an extra £66m to the Revenue to help recover an additional £1.6 billion in tax over three years. He is said to believe there is far more than this to be reclaimed.

Mike Warburton of Grant Thornton, an accountant, said: “It is certainly true that the Revenue is stepping up its efforts to stop people evading tax by moving money offshore. There is a plan to crack down on people with offshore accounts, and I expect thousands of people to be investigated as part of that plan. Some will almost certainly be prosecuted.”

Banks contacted by The Sunday Times denied that they had been ordered to hand over details of credit-card accounts. Nick Gill of Coutts, a leading wealth manager, said: “Obviously we would respond fully if we were approached by the Revenue on this issue. It is my understanding that organisations that receive a ‘production order’ have a legal duty to do so.” Coutts offers offshore US dollar and euro charge cards.

Offshore bank accounts have been the subject of concerted international action in recent years. The main offshore centres — such as the Channel Islands, Cayman Islands and Switzerland — have been cajoled into agreeing to lift their veils of secrecy. This has been enshrined in a European Union savings directive which, unusually, extends beyond the EU to these and other offshore centres.

Austria, Belgium, Luxembourg, the Isle of Man and the Channel Islands have, however, negotiated a transitional arrangement which enables millions of EU citizens to remain anonymous for several years. These centres levy a withholding tax of 15%, rising to 20% in 2008 and 35% in 2011, on foreign holders of bank accounts.

The revenue will be passed back to the holders’ home countries in a lump sum, without identifying individuals, who will still be liable to pay any additional tax due if they are UK residents.