Foreign exchange operators have been attacked by consumers after a survey found customers were being charged up to 8% more at airports than online.
Often the increases are "hidden" with companies offering "commission-free" transactions but then making money on the rate they give.
A Sunday Times report found that a customer changing £500 could be £40 out of pocket at an airport compared to online where rates are much more competitive.
The Financial Services Authority confirmed that it does not regulate foreign exchange which can vary across the country.
Martin Lewis, founder of the Money Saving Expert website, said: "We have a real problem with the lack of foreign exchange currency legislation. The advice is don’t just go and change at the airport. They can charge what they like."
But companies charging higher exchange rates at airports say it is due to higher overheads such as rents and insuring and transporting money and that customers usually pay a bit more for the ‘convenience’.
A spokesman for the Office of Fair Trading said that the issue was not one they had "written off" but that the operators provide robust arguments as to why the charges are higher.
These include high shop rents in airports and costs involved in offering the "convenience".
It advised travellers to access all the foreign currency choices available to them.
