Statistics compiled from all the electoral rolls in the country by a private company, GB Mailing Systems, show that this year more than 44 million people will be eligible to vote in the general and local elections. This is almost half a million more than were registered in 1991, when the effect of the poll tax on voting patterns was at its height.
Though the tax was abolished four years ago, its effects have been slow to disappear. It caused an estimated three million people to disappear from the electoral register.
"I suspect this news would be positive for Labour," said Bob Worcester, chairman of MORI, the opinion poll company. "There's a bias in Labour's favour among the unemployed and working classes, who are the people we could assume would be coming back to the electoral roll now."
Young people also have a definite bias towards Labour, says MORI, which recently found support among 18 to 24-year-olds running at 64 per cent for Labour and 21 per cent for the Conservatives.
The effects of the poll tax on democracy were dramatic. Figures from the Office of Population, Censuses and Surveys show that in 1991, the year after the poll tax came into force over the whole country, the number of registered voters hit a 10-year low, falling by more than 100,000 to 43.5 million, despite half a million people reaching the voting age of 18 in that year.
Introduced to Scotland in 1989 and in the rest of Britain in 1990, the tax obliged councils to impose a flat charge on every adult, regardless of income. Many councils used the electoral roll to build their lists and as a result many people avoided the tax by failing to re-register as voters. MORI estimated that up to 5 per cent of eligible voters did not register to avoid the tax.
"The figures show that the poll tax had the terrible effect of disenfranchising young people," said Jack Straw MP, the Shadow Home Secretary. "I long thought that was probably its purpose. But there are still a lot of people who are not registered, despite the best efforts of local councils."
The figures collated by GB Mailing Systems show that the roll still contains many imperfections. Many people do not vote because they no longer live at the address where they are registered, meaning that the card which is required to cast a vote never reaches them. Mr Straw said: "This does make the case that the other changes that we want, such as a floating register - so that when you move house you can register at once - should also be introduced."