A Manx accounting firm has been advising the super-rich on ways to protect their vast fortunes from inheritance tax, a UK newspaper has claimed.

UK Labour has vowed to clampdown on tax avoidance to in a bid to ensure everyone pays their fair share as it looks to swell the government coffers amid a strain on public services.

Filming conducted by an undercover reporter and published by the Guardian suggests multimillionaire UK residents are being pitched offshore products said to legally protect their fortunes from inheritance tax (IHT) and capital gains tax (CGT).

The newspaper claimed that Isle of Man-based international accountants Baker Tilly told advisers to the ultra-wealthy at a private event how they could use offshore pension schemes to shield clients’ fortunes from the taxes.

Stuart Clifford, a principal at Baker Tilly Isle of Man, was filmed explaining to an undercover reporter at a private event held a week before the general election how one of his clients had placed £30m into a pension scheme to protect it from inheritance taxes.

He went on to say the government would not work to close the schemes down as ministers have ‘bigger fish to fry’.

While the schemes are legal, critics argue tax avoidance is immoral and deprives the public purse of hundreds of millions of pounds that could fund vital services.

The Guardian claim Baker Tilly Isle of Man declined to reveal the value of assets it had helped clients place into these schemes over the past five years, but said remarks attributed to the firm had been ‘taken out of context’.

According to the Guardian, the product the company was promoting at the event is a little-known offshore retirement plan called a qualifying non-UK pension scheme (QNUPS), which is available to UK residents.

The scheme relies on current tax rules that exempt pension assets from certain taxes. Mr Clifford suggested to the undercover reporter that offshore pensions could be used by the rich to avoid future taxes on property investments.

In the footage published by the newspaper, Mr Clifford was filmed telling the reporter using QNUPS to avoid capital gains taxes due on property investments was ‘massive’.

He added: ‘It’s a statutory exemption. It’s not a loophole. It’s not a grey area. It’s a statutory exemption.’

A spokesperson for Baker Tilly Isle of Man told the Guardian: ‘QNUPS, the regulations for which were introduced by HMRC in 2010, is just one of several well-established retirement solutions that Baker Tilly Isle of Man offer as a pension provider to UK and overseas citizens and is at all times administered in accordance with the required laws and regulations in place in the UK. For a pension scheme to be recognised as a QNUPS it must meet strict HMRC guidelines.

‘All of the advice that Baker Tilly Isle of Man gives to its clients is compatible with existing UK legislation and we will of course comply with whatever changes (if any) the new UK government choose to make.’