Regulators are investigating the tactics of "no win, no fee" firms that specialise in recovering bank penalty charges, the BBC has learned.
Consumers are advised not to respond to cold-calls from firms
Since the consumer campaign to recover charges got into full swing, more than 30 no win, no fee firms have sprung up.
They offer to recover charges for a fee of about 25%, but consumer groups say people can do this for themselves.
The newly-formed Ministry of Justice is looking at the sales tactics used by these firms, including cold-calling.
The Ministry of Justice took on the regulation of such no win, no fee firms a few weeks ago from the Department for Constitutional Affairs.
In addition, BBC Radio 4's Today programme discovered that The Information Commissioner's Office is probing the tactics of these firms.
The Information Commissioner's Office is responding to complaints from the public relating to unsolicited automated telephone messages.
The Commissioner's Office has told the BBC that it has written to one claim firm to tell them that such automated messages could breach the Privacy and Electronic Communications Regulations.
Consumer groups warn against responding to unsolicited calls.
"People can stick up for themselves rather than go to these firms, some of which are charging high prices for their work," said Mark Gander, spokesman for the Consumer Action Group.
"There is an organisation that is actually claiming to be us which is cold calling people in this way. This is tremendously damaging.
"The idea of cold calling in this way is disgraceful, anyone involved in this deserves the label of ambulance chaser," Mr Gander added.
On Tuesday, a judge in Birmingham found in favour of Lloyds TSB after it was sued by a customer for imposing supposedly unfair overdraft penalty charges.
District Judge Cooke, at Birmingham County Court, dismissed a claim for £2,545 from Kevin Berwick. Mr Berwick argued Lloyds TSB's charges for having an unauthorised overdraft were illegal contractual penalties.
But Judge Cooke decided that the bank's charges were in fact legitimate fees for servicing an overdrawn account.
The BBC has now learned that the judge in the case has written to a no win, no fee firm warning them that by completing legal forms on behalf of claimants they may be unlawfully acting as a solicitor.
Meanwhile, Conservative MP Andrew Tyrie has proposed that banks should send their customers regular statements of how much they have been charged.
In addition, these statements would include details of how much customers could expect to receive if their current accounts paid an interest rate which was in line with that available to savers.
At present, the majority of current accounts pay a far lower rate of interest than is the case with savings accounts.
This has led to accusations from consumer groups that banks are profiteering from money held in current accounts and that so-called "free-banking" does not actually exist.
The Office of Fair Trading is currently looking into the issue of how free is free banking.