UP TO 500,000 people could disappear from the voting register in the Merseyside area under “devastating” Government plans, a city MP has warned.

Stephen Twigg, the West Derby MP, condemned little-noticed proposals to allow voters to opt out of electoral rolls, removing the current threat of a hefty fine for not registering.

Experts have warned 30% of people currently registered are likely to drop off, partly because the lists are also used for jury service and checks by credit reference agencies.

That would mean around 520,000 fewer people on the register in Merseyside, North Cheshire and West Lancashire, where there are currently 1.58m voters.

The new slimmed-down lists will then be used to redraw the electoral map after 2015, under separate plans to maintain constituencies of roughly equal size.

That will mean the disappearance of more Labour seats in inner-city areas such as Liverpool, it is argued, handing an election boost to the coalition parties. Mr Twigg warned that the proposals would disenfranchise voters, adding: “The mask is slipping on the Government’s hidden agenda.

“Fewer young people, private tenants and ethnic minorities are likely to register. If implemented, this will reduce dramatically the number of inner-city Parliamentary constituencies.”

The warning was echoed at the close of the Liverpool conference yesterday, when Labour’s deputy leader, Harriet Harman, claimed the shake-up was designed to “help the Tories win”, adding: “The Lib-Dems – to their eternal shame – are colluding.”