At present, limited companies are not eligible to have their problems considered by the Ombudsman, although sole traders and partnerships can. Also, the Ombudsman is unable to deal with claims involving sums of more than pounds 100,000.
If limited companies cannot resolve their difficulties with the bank, they face hefty legal bills to pursue their complaints. The lack of a cheap route to redress for small businesses is one of the main complaints of Safe (Struggle Against Financial Exploitation), a bank consumer group launched last month.
This week the Banking Ombudsman, Laurence Shurman, said he believed there was now a real possibility that his remit would be widened to include complaints from limited companies.
He added that his office's resources and staff would have to be increased substantially to cope with the extra workload.
Chris Brown and Carolyn Rothwell, who run a fledgling book publishing company, are typical of the sort of people who might want to take their problem to the Ombudsman but are currently barred from doing so.
They were attracted to National Westminster Bank when they set up their business, Take That, earlier this year, publishing humour books and selling by mail order.
The bank was offering a year's free banking to small businesses that stayed in credit. Mr Brown noticed a clause in the documents that said the free banking perk would be scrapped if the business paid in a large number of cheques.
He says he questioned the bank about its definition of a large number of cheques, and was told that he did not need to worry.
'They said it would only affect large businesses.'
Take That publishes inexpensive humour books and despite the recession has been doing quite well with titles like The Hangover Handbook and Not Madonna's Guide to Sex. The company has paid 580 cheques into its NatWest account in five months.
Take That has now received a letter from NatWest warning that charges would be levied on the account from 19 December.
The charge was 70p per pounds 100 of debits and another pounds 6 a quarter.
Mr Brown and Miss Rothwell feel they are being penalised for their success. They also feel misled.
Ms Rothwell complains: 'I know the bank is not there to be altruistic. But they are supposed to help businesses grow. This does not make sense.'
NatWest's explanation of the criteria for stripping new business customers of free banking was not exactly illuminating.
In a written statement the bank said: 'The volume of transmission activity above which our basic tariff is no longer appropriate depends on the combination of cheques and credits issued, cheques for collection and cash passing through the account.
'An estimate of these volumes is normally sought from new customers so that appropriate rates can be quoted at the outset.'
Customers were given a month's notice of impending charges and were invited to discuss them.
Mr Brown is not taking up the invitation as he has since been offered a better deal by Midland Bank.