The British electorate have overwhelmingly rejected proposals for voting reform in a setback to the coalition government's Liberal Democrats who had championed the change.
Counting in the referendum was still under way but votes against a switch to the "alternative vote" method had already passed more than half the total.
In the first nationwide referendum for more than 30 years, Britons were asked whether they wanted to replace the single transferable vote (STV) first-past-the-post method of electing national politicians with an alternative vote (AV) system in which they could rank candidates in order of preference.
The Conservatives opposed the alternative vote, and the campaigns mounted by the two Coalition parties sparked angry exchanges between ministers. The Labour Party was divided on the issue, though its leader Ed Miliband supported change.
This evening, Lib Dem minister Jeremy Browne acknowledged that the Yes campaign had failed to make “a sufficiently compelling case” for AV.
Counting was taking place in 440 local areas across the UK in the first national referendum since 1975, with the Electoral Commission saying that initial figures showed turnout across the UK ranged from 35.4 per cent to 50.7 per cent.
The No campaign won all of the first nine areas to declare, with 70.27 per cent of votes to the Yes campaign’s 29.73 per cent.
Some of the first results in the AV referendum came in areas held by Liberal Democrats at Westminster - all of them delivering an emphatic rejection of the constitutional change which the party has championed.
The Isles of Scilly was first to declare, with 65.3 per cent support for No, followed by the Lib Dem-held Orkney Islands, with 60.2 per cent for No.
Mr Browne told the BBC: “It already looks like there is a pattern in place. I do think there is an onus on the people who want to make a change to make the case for the change, and the Yes campaign ultimately didn’t make a sufficiently compelling case.”