Imagine for a minute that you are holding an invisible knife. This is a bit like Adam Smith's invisible hand of the market, but a little more real, efficient and effective. You are holding the knife of geographical equality, and will use it to spread something rather than cut. You are about to take the result of the 2010 general election and change history. You are not going to alter a single adult's vote, but you are going to change where they voted. You will swap them with someone who chose to abstain and, by doing so, will smooth out the Tory vote on 6 May.

An analysis of the election results by constituency shows that the Conservatives won 10,683,528 votes that Thursday, equating to 36.9 per cent of all votes cast and 305 seats (not including the Speaker's constituency or the delayed Thirsk and Malton election). Suppose they had won exactly 36.9 per cent of the vote in each seat; the same number of votes overall, but evenly spread. This is what you need the knife of geographical equality for.

What the knife does, as you scrape it across the land, is pick up Tory voters from places where they are more numerous than usual and deposit them in towns where they are lacking. At the extreme, some 14,772 would have to be moved into Dunfermline and West Fife to ensure the 36.9 per cent quota, but most of these could be found from the 13,815 surplus Tory votes in Richmond, North Yorkshire, the seat with the most "wasted" votes.

What effect would the knife have had on the result? The Liberal Democrats would have won 72 seats instead of 57. Labour's number would have stayed the same overall at 258 and the Conservatives would have won only 293 rather than 305. A Lib-Lab coalition could have commanded 330 seats instead of the measly 315 that was contemplated as a block.

But the crucial figure is not how many seats the Tories might have lost, had their support been evenly spread, but how many of their voters would have had to move seat in order for their vote to count. The answer is 1,751,646. That's 16.4 per cent of their entire vote, a percentage which can be called the "segregation index". The Tory vote has not been more unevenly spread since 1918 (at 19.3 per cent). Even as they become more numerous, Tory voters are growing more geographically isolated.

Swing where you're winning

The isolation of Conservative voters has been growing steadily since 1979, when it was half the current level. After it last reached a peak in 1918, it fell, almost continuously, through to 1959. At the same time, the country became less socially and spatially polarised. Wealth and health inequalities narrowed along with those in voting, which became much less of a geographical matter.

From 1959 through to February 1974, the level of Tory segregation remained stable, never going above 9 per cent. In the 1960s and early 1970s, there were Tories everywhere. One-Nation Conservatives had support up and down the country. Then, in October 1974, the segregation index lurched up to 10.7 per cent. New Conservative voters in the Home Counties swung the party's support heavily southwards, while in the north and west it fell. The Tories may have lost that election, but their support had changed geographically and taken the first step on the road towards ever-rising segregation across Britain.

One-Nation Tories felt the cold wind of change. Margaret Thatcher was appointed leader of the opposition the following year. In 1979, she secured her first victory and then, in every general election that followed, including 2010, Conservative support overall increased slightly more where it was strongest to begin with. The segregation index increased the most in 1997, to 13.9 per cent. These may have been "wasted" votes, but they were also one of the many ways in which the 1997 election was no break from the past.

In May 2010, it was voters in the best-off constituencies who swung most firmly towards David Cameron, even though so many in those places already voted for his party. He failed to secure an overall majority because support was lacklustre in the marginal seats. The last Tory leader who saw the segregation level of his or her vote fall while in office was Ted Heath in the early 1970s. In 2010, support swung away from the Tories where it had already been lowest in 2005.

What does this say for the future? It tells us we are living in remarkable times. The segregation of the Tory voter is greater now than it was in 1922, and it has been that high and rising since 2001. That the Conservatives won the largest minority of seats in a general election, while seeing the greatest increase in support where they needed it the least, shows how little empathy most people in Tory shires now feel for those who live in the cities, or the north, or the countries outside of England.

Kings of the hill

In Sheffield, where I now live, it felt like an apathetic election. Hundreds of volunteers were pushing leaflets through doors, but there seemed to be fewer posters than before, despite that brief spell of Cleggmania infecting his adopted city. A few days before the election, I went back to Oxford East, where I grew up, and was shocked to see so many Labour posters again. Perhaps I should not have been surprised when people in that constituency gave an overall swing to Labour.

I also went to nearby Witney, Cameron's seat, and passed posters for Ukip and the Tories (marking out the field boundaries of wealthy farmers, rather than council estates). I asked people there what they thought would happen to the economy after the election and some told me a flood of cuts was coming, but Witney was (metaphorically) "on a hill" and would be OK, especially if they voted for "Dave".

The people of Oxford East have been surrounded by Conservatives for generations. With hindsight, it is not surprising where voters swung; but these two Oxfordshire seats represent in microcosm what has occurred across the country. Those who have most have voted to try to hold on to as much as they can. Those who have less have not been fooled.

The previous 1918 peak is almost 3 per cent higher than today's figure, so there is a precedent for the country to become even more geographically divided. But 1918 was a very strange election (see box left). In many other ways, we have already become more unequal than we were then - in terms of what matters (health) and what we think matters (wealth).

The early casualties of the cuts are the poorest in Britain, who have already disproportionately lost their jobs and their chances of a better home, or even of a holiday, this year. Fear drove those who have the most to vote in greater concentrations to cling on to what they've got.

We all need a politics we can better trust. In more equitable times, we didn't need the knife of geographical equality to help us understand elections. But then, people who voted for different parties lived nearer to each other.

Danny Dorling is the author of "Injustice: Why Social Inequality Persists" (Policy Press, £19.99)

1918 - the "khaki election"

The 1918 election, the first to be held under universal male suffrage (most women had to wait until 1928), was notable for bringing about the sort of pact between the Conservatives and the Liberals that some expect to see in 2015. Candidates who enjoyed the official support of the coalition government received a letter of endorsement from the Liberal prime minister, David Lloyd George, and the Conservative leader, Andrew Bonar Law - a document that was seen as crucial proof of their patriotic credentials.

The "khaki election", so known for its postwar setting, was won by the coalition parties and, after his successful wartime stint, Lloyd George remained prime minister. The Conservatives increased their seats by 61 to 332 and the Coalition Liberals, standing under that banner for the first time, won 127. The anti-coalition Liberals, led by the former prime minister Herbert Asquith, won just 36 seats, an event that many believe marked the beginning of the end of the Liberal Party as a significant force in British politics. Meanwhile, Labour more than trebled its share of the vote from

7.1 per cent to 21.5 per cent, but ended up with 57 seats - a net gain of just 15.

There was better news for Sinn Fein, which won 73 of Ireland's 105 seats, ushering in the UK's first ever female MP, Constance Markiewicz.

George Eaton