Which? research found that more than half of the advisers questioned refrained from revealing how much they charge until customers meet with them in person.

The vast majority investigated also did not mention their prices on their websites, Which? said.

Posing as potential clients, Which? called 30 independent financial advisers (IFAs) asking how much it would cost for advice on investing a £60,000 inheritance, but only 14 of them could be pressed to reveal their fees over the phone.

Which? said: “Many advisers told our researchers that their charging system was much easier to explain face-to-face, whilst some suggested it was impossible to establish costs without more detail.”

Others were more than happy to indicate how much their service would cost without engaging in lengthy meetings, it added.

The organisation also carried out a survey of 206 IFAs, which revealed that advisers were most likely to charge an up-front fee calculated as a percentage of the investable assets.

The regulator had previously warned that such a method may not fit in with RDR philosophy but advisers and clients have said they preferred it to other charging methods.

Which? said it has shown its findings to the Financial Conduct Authority (FCA) which agreed that more needed to be done to achieve transparent pricing in the industry.

A Which? spokesman said: “We want to see all financial advisers publishing their full menu of charges online, and if this can’t be can’t be achieved by industry-led initiatives, we want to see the FCA regulating advisers to compel them to do it.

“We think it’s important for independent financial advisers to adhere to the spirit of the rules as well as the rules themselves, and this means being open about how much they charge, enabling consumers to shop around.”

Advisers were forced to implement transparent client agreed renemeration by the RDR which came into force in the beginning of last year.

Many firms had already had fee-based charging structures in place before the deadline.

The UK arm of global independent advisory firm deVere, has warned consumers to be cautious of financial advisers who charge for an initial meeting and who are not upfront about fees from the outset.

deVere United Kingdom head of Financial Planning Kevin White said: “There is absolutely no excuse for financial advisers to ‘swerve the question’ about how you will be charged and how much the advice will cost.

“Besides the obvious ethical reasons for being totally upfront on fees, and because RDR now demands it, we do not see the logic behind being anything less than transparent.

“[Which?’s findings] are particularly alarming because [they] could potentially deter people from seeking professional financial advice at the very time when, due to the deepening pensions crisis, amongst other important factors, it has never been more important to do so in order to achieve your long-term goals.”