The lifetime allowance – the amount of money you are able to save into a pension without incurring a tax charge – was cut from £1.25m to £1m in April.

But worrying numbers of middle earners, many of whom think they have accumulated far less than £1m, risk receiving an unexpected tax bill.

Mitch Hopkinson, head of advice at deVere United Kingdom, said before seeking out financial advice, as many as two thirds of new clients had been at risk of breaching the reduced lifetime allowance.

He said: “Previously only the highest income earners were likely to be caught out by the LTA threshold.  But thanks to repeated cuts in the value of the allowance – the latest in Chancellor George Osborne’s 2015 Budget, in which it was cut to £1m – middle England is really being hit.  A surprising amount of people simply don’t realise that they could be slapped with a tax bill for breaching the limit.

“£1m sounds like a lot, but when you take into account investment growth, you could find yourself inadvertently going over that threshold a lot easier and sooner than you might think.”

Hopkinson warned members of defined benefit schemes could hit the reduced LTA limit without realising because employers offering these pensions “aren’t always great at providing advice” and employees tend to only review their pots at retirement, at which point they could be hit with “draconian 55% tax rates”.

Defined contribution pension holders are also at risk because they often don’t factor in future growth, he said.

If you reach the LTA threshold how you are taxed will depend on whether you take the excess as a lump sum or as income.

Those who take the extra as a lump sum will pay 55% upfront and the remainder will be paid directly to them. Those who decide to take it as income will pay 25% upfront and the remainder is put into the rest of the fund, which is taxed at marginal rates.