The collapse in Labour’s vote at Thursday’s local elections marks the end of the electoral coalition that Tony Blair believed would enable his party to govern for much of the 21st century in the same way as the Tories dominated the 20th.

Voters across large swathes of the south and Midlands who had so enthusiastically flocked to new Labour in the 1997 landslide have rejected the party. The map of England’s shires is almost unremittingly blue and Labour has 50 fewer county councillors than even at its previous low point in 1977.

Taking into account the likely previous results in councils where there has been a reorganisation or boundary change, Labour lost two-thirds of the 500 seats it was defending. The Tories emerged nearly 300 seats up, winning more than six of every 10 seats contested, while the Lib Dems fell back a little.

Current discontent with politicians of all parties did not appear to have much effect on turnout, which was around the long-term local election average of 35%. It was, however, reflected in isolated successes for minor parties. The Greens, British National party and UK Independence party all advanced by a handful of seats, but were themselves often overshadowed by locally based campaigning and community groups.

In an exclusive analysis for The Sunday Times, we have examined the votes cast by more than 4.5m voters in more than 1,200 local divisions and wards contested by at least the three major parties in order to calculate how they would have fared if these elections had taken place in every part of the country.

This analysis has the Tories on a national equivalent vote of 35% (a four-point increase since the local elections in 2005). This is below the symbolic 40% mark, but still with a comfortable lead over Labour who are at a historic low of 22% (down 12 points). The Lib Dems scored 25%, down two points from 2005.

The “others” often polled heavily without winning, and in almost one in six wards their presence led to a fall in the share of the vote for all three major parties. Their total share of 18% is likely to seem comparatively modest when the European parliament results are declared later tonight.

The minor parties will, however, struggle to do as well at a general election. Adjusting the vote shares to reflect the differences between local and general election voting seen in 2005 when the polls were held on the same day, we project the Tories to be on course for an overall majority of 34. They would win 342 seats compared with 212 for Labour and 63 for the Lib Dems.

If the local share of the vote was a little disappointing for the Tories, they more than met expectations in terms of seat gains. Labour lost all four of the counties it was defending directly to the Tories. Derbyshire, Lancashire, Nottinghamshire and Staffordshire are now in Tory hands for the first time in more than 30 years.

Nor in most cases was it a close run thing. Labour has been reduced to just three councillors (from 32) in Staffordshire, and lost more than 20 seats in both Lancashire and Nottinghamshire.

Each county contains a raft of pivotal marginal constituencies. Hyndburn, Lancashire is significant because it is the constituency that would give the Tories an overall majority on the basis of gaining 116 seats on a uniform 6.9% swing from Labour. The Tories were just ahead on Thursday, but both the number of seats and the size of the swing required show how tough their task remains even given Labour’s dismal showing.

Blair won in 1997 following a 10.2% swing, though needed nothing like that to take power: the previous record post-war swing was Mrs Thatcher’s 5.3% in 1979.

The parliamentary seat which has suddenly come into the political spotlight is Norwich North, where Ian Gibson’s resignation as an MP will trigger a by-election. Labour will defend a majority of 5,459 in a constituency where the old boundaries no longer match existing local government wards. The Greens are strong in Norwich itself, but the Broadland part of the seat was clearly in the Tory column last week. The swing needed is just 5.8%.

Equally satisfactory for the Tories were their results in the three counties of the far southwest where they gained more than 50 seats. They took control of both Devon and Somerset from the Lib Dems and are the largest single party in the new Cornwall council, itself previously a Lib Dem fiefdom.

The Lib Dems can point to their own more modest successes, most particularly the sweep to power in Bristol. It is noticeable that here, as in other pockets such as Ashfield in Nottinghamshire and Burnley it was Labour rather than the Tories that they damaged.

The authors are co-directors of the LGC Elections Centre, University of Plymouth

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