In recent months many councils have toughened up their bill- collection procedures to bridge the gap caused by reduced government grants.
Moira Haynes, spokeswoman for the National Association of Citizens Advice Bureaux, says: "People have been coming into the bureaux all over the country faced with bills for poll tax which they are sure they have already paid, or for which they were never liable. This far down the road it is very difficult to prove that you paid a bill in 1990.
"In one case a person in the North-west was faced with a bill for pounds 700 and had a bank statement proving payment, but the council concerned will only accept a copy of the cheque and the bank has now destroyed them for this period," continues Ms Haynes.
"In another case, someone paid in cash and received a bill in excess of pounds 1,100 for 1992-93. They no longer have a copy of proof of payment. In this case, the council finally accepted that it was in error because of computer problems, but that raises the question about how many more errors have been made.
"In other cases people who were not even living in that town at that time are being given bills, but it is very difficult to prove where they were living.
"A Midlands council sent a bill to one woman for three years while she was living elsewhere and unemployed, but she was unable to prove it," says Ms Haynes.
Some law practices also have a number of clients who are disputing old poll tax bills. Richard Wise, a lawyer with the Clyde, Chappell and Botham firm of solicitors in Stoke, says: "The reality is that the accounting systems that some councils set up in the early days were inadequate. At one Midlands council a lot of incoming post went missing and they can't prove whether money went missing. There are a number of cases where people say they paid bailiffs and the money was not passed on. There has been a criminal investigation into bailiffs in one city."
Citizens Advice Bureaux in Islington, north London, have been deluged with inquiries since the council sent out 30,000 demands last September for payment of old poll tax bills, representing pounds 17.8m of outstanding debt. Many of those who received demands have told the bureaux that payment was made several years ago, but they no longer have personal finance records from that time to prove it.
Ian Thorn, chief whip for the opposition Liberal Democrat group in Islington, says: "This does not surprise me given the shambolic way Islington manages its finances. We have pounds 4m of uncollected parking fines, equivalent to a whole year's issued parking fines." This figure, calculated by the district auditor, is disputed by the council.
A spokeswoman for Islington council says the bulk dispatch of letters has led to a huge rise in payment of old debt. "People assumed that when the council tax came in they did not need to pay old poll tax bills, and were genuinely unaware they still had to pay outstanding bills. With any system that has many thousands of entries, mistakes do happen, but we are not aware of problems on the scale that is suggested."
Dave Nellist, the former Labour MP who was one of the leaders of the Anti-Poll Tax Campaign, is now an advice worker for Robert Zara, a firm of solicitors in Coventry. He suggests that people who are in arrears on their poll tax, and cannot afford to pay all their debts, should take advice on applying for an administration order from the courts, which will allow them to pay all their bills in an ordered fashion, without the risk of being sent to prison.
Mr Nellist also points out that people who have not had a liability order issued against them through the courts are not liable for poll tax debts after seven years. The poll tax was in place from 1990 to 1993, so some early debts will soon no longer be legally enforceable.
The National Association of Citizens Advice Bureaux is calling for councils to adopt a more reasonable approach. Ms Haynes says: "We would like to see councils provide proper documentation to prove non-payment. They are currently requiring a standard of proof from other people that they are not providing themselves.
"We also want to see councils much more sensitive to the fact that after such a long period of time has elapsed, enforcement action is not appropriate. They should be prepared to write off debts and admit it when they have got things wrong."