People who avoid paying tax by hiding their money overseas could face jail under sweeping new regulations being planned by the Government.
Chancellor George Osborne is consulting on the creation of a new criminal offence to make it easier to prosecute British citizens who hold undisclosed money in offshore accounts.
The changes would give HM Revenue & Customs the power to prosecute people who do not declare their foreign income, even if they did not deliberately intend to avoid payment.
It will mean HMRC only has to demonstrate the income was taxable and undeclared, meaning it will be easier to secure successful prosecutions of offshore tax evaders.
Speaking from the International Monetary Fund meeting in Washington, Mr Osborne said: "We are changing the balance of the law, so HMRC don't have to prove someone intended to hide their money offshore to evade tax, just that they did so and didn't pay tax.
"The message is clear with this new criminal offence: if you are evading tax, there is no safe haven and we will find you."
HMRC has come in for criticism for the small number of tax evaders it prosecutes and the threat of prosecutions is likely to persuade more tax avoiders to come forward.
A document being published on Monday will outline the details, and the new criminal offence and sanctions are expected to come into effect next year, with HMRC receiving information on offshore accounts from 2016.
The Government will also consult on a range of options to bolster existing penalties - currently up to 200% of the tax owed - faced by those hiding their money in offshore accounts, including whether to raise the existing penalty limit and extending the regime to include Inheritance Tax.
Whistleblowers could also be rewarded for significant information that helps uncover offshore hidden untaxed assets, the Treasury said.
But the announcement was greeted by dismay from some, with critics suggesting the law could result in people being jailed when they were genuinely ignorant of the law.
Bill Dowdell, head of tax at Deloitte, told The Times: "It's horrifying. People should not be put in prison unless you can prove intent. I'm shocked to find that an offence which could lead to a prison sentence could be decided on a strict-liability basis.
"If this change applies to all evasion cases I think that's unacceptable. People should not be put in prison unless you can prove intent."
Jonathan Isaby, chief executive of the TaxPayers' Alliance, said: "It is absolutely right that people who break the law and illegally evade their taxes should face prosecution. But there are more fundamental problems with our tax code, which is far too complicated.
"Politicians need to make our taxes simpler, fairer and more competitive if they are serious about curbing tax evasion."