The way we run local elections misrepresents the will of voters – particularly in Swindon – says pressure group the Electoral Reform Society.

Analysis of May’s local elections by the group shows that Swindon had the second highest gap in the south west between votes cast for the winning party and its number of seats.

While the Conservatives, who increased their majority at the elections, received 39.6 per cent of the votes cast, the party won 12 of the 19 seats up for grabs – 63.2 per cent. The gap between votes cast and seats won is 23.5 per cent, putting the borough second only to Exeter of authorities in the region which held elections third year.

The group, which campaigns for changes to voting systems, says councils are allowed to use the single transferable vote system, which allows electors to make a second and possibly third choices. This means the winning candidate has to have at least 50 per cent of all the votes cast.

Jess Garland, director of policy and research at the Electoral Reform Society, said: “This research shows how our broken electoral system is distorting local election results. First past the post is delivering skewed results across the south west, meaning many voters’ voices are unheard.

“England continues to rely on this disproportionate system for local elections, where only the votes for the top candidate to ‘get over the line’ secure representation – all others are ignored. Spread out over thousands of contests, this can lead to some parties being drastically over or under-represented.

“In comparison, Scotland legislated to use the more proportional single transferable vote. Since 2004, voters rank candidates by preference and ‘surplus’ votes are redistributed according to voters’ choices. Most advanced democracies use proportional systems where seats more closely reflect parties’ share of the vote.

“It’s time we ended the broken first-past-the-post system in England – a system that continues to warp our politics. A more proportional system would help open local democracy and make sure all voters’ voices are heard.”

Leading opposition councillors in Swindon backed up that view.

The Labour group leader, councillor Jim Grant, said: “I completely agree with the Electoral Reform Society. Labour and the Conservatives practically got the same number of votes across the town and yet the Conservatives have got over the 60 per cent of the seats. People might argue that such a drastic difference makes this an illegitimate election with so many people's votes wasted.

“I have always been a believer in proportional representation as it gives everybody a meaningful vote. At present there are too many areas in Swindon where people’s votes don’t really matter as the outcome of ward-based elections are already known. Swindon deserves better.”

Councillor Stan Pajak is the leader of the Liberal Democrat group. His party has always made a campaign platform of changing the voting system.

He said: “It won’t surprise you to learn that I’m not in favour of first past the post. It doesn’t reflect the votes cast and it means that people also think there’s no point in voting for smaller parties – they have to choose between one of two parties that can win.

“If we move to elections once every four years, I think it’s even more important that we have a much more representative voting system.”

But deputy leader of the council, and the ruling Conservative group, councillor Russell Holland doesn’t agree.

He said: “I don’t think there’s much of a desire to change the system.

“First past the post is simple and is easily understood my everybody and is a clear system. It gives a clear winner. There’s not a huge movement to change it, and we had the alternative vote referendum in 2011 and I think first past the post won that with more than 60 per cent of the vote.

“You also have to remember that we elect people as councillors. They might stand for a party, but you are electing an individual and when elected they represent all their constituents, however they voted.

"We should keep the system we have.”