The General Election may be the closest in recent years, but a group calling for changes to the UK's electoral system say most results are a foregone conclusion.

Although the General Election is four weeks away, the Electoral Reform Society says winners can already be predicted in nearly 69 per cent of seats in London.

London has the fifth highest proportion of ‘safe seats’ in the UK, and the society has called the results 50 of the capital's 73 constituencies.

According to its study, Labour’s Barry Gardiner will win the seat in Brent North, while the Conservative Party’s Nick Hurd will also retain his Ruislip, Northwood and Pinner constituency.

As both Harrow East and Harrow West are marginal seats, the society has been unable to predict the outcome.

Katie Ghose, chief executive of the Electoral Reform Society, said: “The fact that we can firmly predict the outcome of more than two thirds of seats being contested in London this May is a sorry indictment of our outdated voting system.

“The average UK constituency hasn’t changed hands since the 1960s, and some have been under the same party’s control since the reign of Queen Victoria. 

“We urgently need a fairer electoral system to give voice to the many millions of people in safe seats who are not being heard.”

Nationwide, the ERS has confidently predicted the winners in 368 seats – 57 per cent of the total – based on the winning margin in 2010 and current national and local opinion polls.

The analysis finds that of the 303 Conservative seats, 190 are safe, while of the 257 Labour seats, 150 are safe.

Just seven of the 56 seats held by the Liberal Democrats have been deemed safe.

The ERS’s work highlights the fact that despite the overall outcome of the election being unclear, the majority of seats can still be predicted because of Westminster’s 'first past the post' voting system.

Ms Ghose added: “Predicting the winners in a majority of seats shouldn’t be possible in a truly dynamic and modern democracy. But sadly that’s exactly what we’ve been able to do.

“The UK needs a fair voting system to bring our politics into the 21st century and give us a parliament that actually reflects people’s wishes.”

The ERS has also developed an online tool allowing people to see whether they live in a safe seat or not, simply by entering their postcode at http://action.electoral-reform.org.uk/ea-action/action?ea.client.id=1754&ea.campaign.id=37376