Hundreds of wealthy UK taxpayers have been sent letters by HM Revenue & Customs over possible large-scale tax evasion, the BBC has learned.

It is understood HMRC has acquired a list of high net-worth individuals with accounts at the Swiss division of HSBC.

The list was stolen by an employee and passed to the taxman by the French authorities. The bank is not accused of any wrongdoing.

The campaign comes after the government announced a crackdown on tax avoidance.

Chief Secretary to the Treasury Danny Alexander told the Liberal Democrat conference in Liverpool it was hoped closing loopholes and ensuring wealthy people pay the full top rate of tax would generate an estimated £7bn a year by 2015 in additional income tax revenue.

This is a grey area in my book.

Lets face it we all hate paying tax and we all minimise what we pay where we can. Its just how close to the law you are prepared to go.

Yes but they already have enough legal loophole to reduce their tax rate to lower than the average person. Without even hiding it illegally.

There was an amnesty in place until not long ago for poeple in this position, just had to declare how much and pay some back tax. Now will get to pay back tax and penalties as well. Can't say I'm upset.

Sod the penalties, how about full on recriminations?

If ever I was fortunate enough to have the kind of money those people have, I'd like to think it wouldn't turn me into a criminal and I would continue to pay my share of tax.

Yes you can go to prison for non payment of a TV license which is a tax. On that basis these people should be doing serious gaol time.

It's possible they could. Unlikely though.

interesting ethical question there. Using illegally obtained information to use against other people. End justifying the means?