There is a "postcode lottery" over foreign exchange, according to consumer group Which?.
Researchers were sent out around the UK to mystery shop major currency exchanges. The consumer group found significant regional differences in how many euros were offered in branches of the same provider. The UK's biggest provider of foreign currency the Post Office, was particularly at fault.
In post offices in London and Glasgow the researchers were offered €578.50 for £500 but this dropped to €574.85 in Manchester, Norwich and Southampton branches. The lowest exchange was €565 in Birmingham, Haverfordwest and Sheffield.
The rates offered by Thomas Cook had even bigger differences with the best, €585, offered in Sheffield. In Glasgow, Leeds, Haverfordwest and Croydon €583 was paid while Birmingham and Southampton quoted €580; London €575.80; Norwich €575; and Manchester €553.80.
"We understand local competition may play a part in the rates, but it is unfair people miss out on the best rates because of where they live. Currency providers need to make rates consistent to ensure a fair deal for everyone," Richard Lloyd, Which? executive director, said.