Proportional representation could stop extremists like the British National Party taking council seats despite low support, campaigners said today.

A switch from first past the post to PR has traditionally been thought to benefit minority parties.

But the current system cheats those who would rather have anyone representing them than the BNP, according to the Electoral Reform Society.

The party’s gains on councils in the north have caused widespread concern.

Chief executive Ken Ritchie said PR could reverse them and break the stranglehold the three main parties have on councils in some parts of the country.

“The changes we are putting forward are more likely to reduce the representation of the Labour Party in some parts of the north of England, in other parts it might be the Conservatives, in another it might be the Liberal Democrats,” he said.

“We simply want to see fair representation.

“We want to see local councils that are more representative of the communities that they serve.”

Mr Ritchie told BBC Radio 4’s Today programme: “It might be that a party like the BNP gets a third of the votes.

“It may be that the other two thirds of the voters would prefer to have anybody other than a BNP councillor.

“But if that two thirds is spread over the other main parties then it only needs a third of the votes to win.

“Therefore smaller parties like the BNP, if they get to this threshold where they are winning seats, they can win a majority of the seats on a council on very much a minority of votes.

“We have seen that happening not with the BNP but with other parties who win a majority on a council with a minority of the votes.”

Mr. Ritchie insisted the society, which publishes a report on the issue today, was not out to thwart the BNP.

“We rejected a system that would have made it almost impossible for the BNP to win seats,” he said.

“We want all legitimate parties, all parties that are operating and campaigning within the law, to have an equal chance.”