500,000 votes not counted

Huge numbers of electors lost their say in the mayoral and London Assembly elections when more than half a million votes were rejected.

Voters baffled by the different systems used to elect the Mayor and assembly members ended up marking their ballots in the wrong places, rendering them invalid.

Some 385,952 votes were unable to be counted for the mayoral poll and a further 167,071 were ruled in breach of rules for the assembly election.

Electors had been asked to cast first and second preference votes for a mayoral candidate and two votes for the London Assembly - one to elect a local constituency member in a similar way to electing an MP, and the other to choose a party to represent the city on a "Londonwide" basis.

But problems arose primarily because voters placed their first and second choices for Mayor in the same column rather than adjacent columns - making it impossible to determine which candidate should get the first preference vote.

In the assembly ballot, many crosses were placed across two boxes, again making it difficult to calculate the elector's intention. A number of ballot papers also had to be scrapped because election officials accidentally tore through a crucial barcode when they handed the papers to electors.

The barcodes were needed to allow the votes to be counted by machine rather than by hand and ensure their legitimacy. Londoners faced further confusion this year because they were also asked to vote in the European elections. This meant they were asked to place five crosses on three separate ballot papers, with each election being conducted under a different voting system.

The independent organisation responsible for the electionsis blaming the Governmentfor failing to heed warningsafter similar problems occurred in the first London elections in 2000.

Deputy returning officer John Bennett of London Elects said the Government had failed to find time to pass new laws simplifying the voting process, despite being made aware of widespread concerns. "The Government only had a particular window of opportunity to change the legislation and we missed that window," he told the BBC's Politics Show.

He said the number of spoiled ballots - which was actually slightly lower than in 2000 - needed to be investigated by the Electoral Commission, political parties and Electoral Reform Society.

Ideally, clear guidance to voters should be marked at the top of each paper, with separate ballots being used for the two assembly sections, he said.

Politicians expressed dismay at the number of wasted votes but said it was unlikely to have changed the outcome of the elections.

Lord Tope, Lib-Dem group leader on the London Assembly, told the BBC: "I don't think any of us is suggesting the result would be different."

Bob Neill, a Conservative member of the London Assembly, said: "There were a lot of instances where people have marked their two crosses in one column."

A spokesman for the Electoral Reform Society said: "There needs to be a review of why so many people's votes didn't count. I don't think this was a very satisfactory outcome."