Geoff Boucher raised his concerns despite broadly welcoming the policy.

HMRC figures from pensions show that £6.7 billion was withdrawn by 375,000 investors in the last 12 months and £17.5 billion has been withdrawn from pensions since the freedom changes were introduced April 2015.

That, Mr Boucher insisted, was a good thing.  

He said: “The pension freedoms are fundamentally beneficial for people, giving them welcome control and flexibility over their retirement savings.”

But he warned: “These reforms have also increased the risk of retirees being targeted by scammers.”  

He added: “Some pensioners have chosen to invest without taking professional advice.

“This DIY approach of chasing higher returns could be exposing them to a high level of risk as many are unregulated, illiquid and based on high commission rates.

“At worst, they could be increasingly exposed to fraudsters.”

The fears echoed TPR acting executive director of regulatory policy, Anthony Raymond, who voiced his concerns at the Association of Member-Directed Pension Schemes (AMPS) Annual Conference in London recently.

He said: "There’s no point in sugar-coating it, the damage is done the moment a pension is transferred out of a safe scheme into the unknown.

“There are some very clever and very devious people waiting to cash in on vulnerable people.”