The HM Treasury courtyard, Whitehall, London.

The UK revenue agency on Tuesday is due to announce stiffer penalties for offshore personal tax evaders after raising £1.5bn in revenue through increased payments and penalties over the last two years.

HM Revenue & Customs will launch a consultation on a new criminal offence of failing to declare taxable offshore income and gains, including safeguards to ensure the “proportionality” of the measure.

Last April George Osborne, chancellor of the exchequer, announced that the government would consult on plans to introduce a new strict liability criminal offence for individuals who hide their money offshore.

Under the plans announced by the chancellor, HM Revenue & Customs (HMRC) would no longer need to prove that individuals who have undeclared income offshore intended to evade tax, in order for a criminal conviction to be handed down.

At present, HMRC has to demonstrate that even when someone failed to declare offshore income, that the individual intended to evade tax. This change 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.

As well as introducing the new criminal offence, the government will consult on a range of options building on the existing penalties faced by those hiding their money in offshore accounts - - currently up to 200 percent of the tax owed - - to make sure they act as a clear and effective deterrent.

The consultation was set to look at whether the existing penalty limit should be raised further, how penalties could be increased if individuals try to move money around in a bid to avoid detection and extending the penalty regime to include inheritance tax.

HMRC said the offence would apply to cases over a certain threshold, ensuring that only “significant” non-compliance was punished.

The current limit of 20 years on how far back investigations should go, is expected to be abolished.

A person’s state of mind will not be accepted as a defence meaning the prosecution in a court will only need to demonstrate that a person failed to correctly declare the offshore income or gains, and not that they did so with the intention of defrauding the Exchequer.

The International Adviser website says that  David Gauke,, financial secretary to the treasury, said that those using offshore secrecy to evade UK tax are making a “big mistake”.

“Thanks to this government’s leadership, countries across the world have agreed to share information on offshore account,” he said. “Over 56,000 people have already told HMRC about what they owe offshore, and it has offered opportunities to clear things up as quickly and easily as possible.

“Those that don’t come forward must face tough consequences, including a criminal conviction.”

Last week, HMRC and the Government of Liechtenstein agreed to prevent users of UK employee benefit trusts (EBTs) from reaping the benefits of the Liechtenstein Disclosure Facility (LDF).

Separately, up to a quarter of a million European migrants will pay tax in Britain for the first time, under plans being prepared by George Osborne, the Daily Telegraph reported last week.

Temporary workers from the European Union will be stripped of the right to use the £10,000 tax-free personal allowance under Treasury proposals.

It means that up to 250,000 labourers, agricultural workers, cleaners and bar staff from the EU working in Britain who currently earn less than £10,000 will pay tax on their earnings for the first time. It means that, in effect, they will earn 20 per cent less than their UK counterparts who will be able to keep all of their earnings below the personal allowance.

Tax experts suggested the move would result in fewer migrants coming to Britain for temporary work.