Jenny Watson, chairwoman of the Electoral Commission, said this weekend that accuracy was more important than speed
David Cameron, the Tory party leader, may not know for sure whether he has won the general election until 24 hours after the polls have closed because of delays in counting the ballot papers.
New figures from the Electoral Commission watchdog reveal that the results of one in three of the 650 constituencies may not be declared until the day after the election.
According to the Electoral Commission, returning officers for 64 seats - many of them key marginals - say they will wait until the morning after the election to begin their count. Another 161 are considering following suit.
The delays, caused by council budget cuts and new red tape, mean that if the election is close the outcome may remain unknown on election night.
The new timetable is threatening to rob television of the live drama that traditionally ensues after the polls shut at 10pm and to end the long-established practice of the removal vans of victor and vanquished crossing in Downing Street on the Friday.
Jenny Watson, chairwoman of the Electoral Commission, said this weekend that accuracy was more important than speed. "The worst-case scenario is the result being called into question because the count is inaccurate," she said.
Recent polls have shown the gap between the two main parties narrowing, indicating a small Conservative majority or a potential hung parliament.
The constituencies where counting is being delayed include key Tory target seats such as Watford, Wolverhampton South West, Northampton South and North and Milton Keynes North and South. Derby North, which the Conservatives need to take from Labour to ensure an overall majority, is also set to state its count on the Friday after the Thursday ballot.
Council returning officers complain that under-funding means they can no longer afford to employ extra staff overnight to help with the count.
However, Watson said the main reason for the delays was new rules on postal votes. "Returning officers will have, for the first time, to check some additional security information on postal votes," she said. "A lot of people hand in their postal votes on the day rather than put them in the post beforehand."
She also warned that 3.5m adults could be disenfranchised because of local authority failures to persuade people to put their names on the electoral roll.
"Our research published after the last general election showed that between 8% and 9% of the population of England and Wales were not registered to vote," she said. "The evidence coming through since then suggests the picture isn't getting any better."
Watson said that in past elections, gaps in the registers had not been a problem on polling day. However, the MPs' expenses scandal and the potentially close result could motivate many previously apathetic voters to want to take part.
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