This year’s Labour party conference was accompanied by little of the triumphalism with which the Tories celebrated their third successive term in October 1987. For all its supposed arrogance, Labour lacks the kind of confidence the Conservative party used to have in both its natural right to govern the country and the innate rectitude of the policies it pursued in office.

But psephological, as opposed to psychological, differences also play a large part in explaining the lack of similarity in the manner in which the two parties reacted to their electoral hat-tricks. It was these that dominated discussion on the conference fringe in Brighton and, two weeks later, at Progress’ annual conference in London.

Compare Labour’s victory in 2005 with Margaret Thatcher’s in 1987 and the scale of the challenge for the party over the next four years becomes clear. At 42 per cent, the Tories’ share of the vote in 1987 was up marginally on its 1983 score and down a touch on its 1979 vote. And, on a roughly comparable turnout, the Tories succeeded in securing more actual votes than in either 1979 or 1983. The Tories’ confidence was also boosted by the knowledge that, despite the strength of Neil Kinnock’s first challenge to them as party leader, they were a clear 11 points, or three million votes, ahead of Labour.

By contrast, Labour’s win this year was, as has been much remarked, secured with only 36 per cent of the vote – down by nearly six per cent from 2001. The party beat the Tories by only 700,000 votes; barely a three per cent lead. Most damagingly of all, as turnout has fallen, Labour’s vote has dropped by nearly four million from its initial victory in 1997. It is, in fact, just below the 9.59 million votes secured by John Major as he headed for catastrophic defeat at Tony Blair’s hands eight years ago.

Put this way, Labour was wise – even if it had been so inclined – to avoid any hint of self-congratulation or self-satisfaction. More damaging still, however, would be for the party to seek or adopt some of the quick-fix solutions that were on offer to it in Brighton. The notion, for instance, that Labour’s loss of seats and votes to the Liberal Democrats legitimises a simple shift to the left away from the centre ground is wrong-headed. For Labour to adopt this strategy, as both the Conservatives and Liberal Democrats debate how they can adopt a greater appeal to the mass of the electorate that places itself in the centre (see On the Radar), is a sure route to electoral defeat.

This view also ignores the fact that, while the Tories may have flat-lined in the general election, it was still they who inflicted the most damage on Labour. The party must not forget that, at the next election, it will be defending 20 seats with majorities of less than 1,000; in 16 of which, it is the Tories who are the main challengers. Indeed, of Labour’s 50 most marginal seats, the Conservative party is in second place in no less than 42. As Liam Byrne argues in the recently published Fabian Society pamphlet Why Labour Won, ‘if we win back Cambridge, but lose seats such as Crawley, Dartford, Selby and Gillingham, we will be out of power again.’

Labour must, therefore, remain unshakeable in its attachment to those ‘new’ Labour principles – fiscal discipline, reform and investment in public services, an understanding of the changing aspirations of the British people, and a belief that the values of personal responsibility and opportunity must animate our approach to social policy – which speeded the party’s electoral recovery in the 1990s.

Equally, however, we reject the notion that, because the primary threat to a fourth Labour term comes from the Conservatives, we should ignore the very real damage that the Liberal Democrats can do to Labour. Labour may have lost only a dozen seats to the Liberal Democrats, but 16 of the Tories’ 31 gains from Labour can be attributed to defectors to the Lib Dems. More crucially, Labour needs to seek to understand why so many of our natural supporters felt more comfortable voting Liberal Democrat.

Overall, we believe this has much less to do with individual issues like Iraq, tuition fees or civil liberties – however important they may be – than with a general perception that questions Labour’s attachment to progressive values. And, however trite it may be to suggest it, this problem stems in part from a failure of communication. Labour has, as Neil Kinnock has argued, failed consistently to ‘publicly connect accomplishment with purpose’.

The party has also suffered from an unwillingness – attributable to a misplaced fear of offending middle England – to proclaim the radical nature of Labour’s agenda on a range of issues: from the reduction of child poverty to urban regeneration and the drive against social and economic inequalities. Where the party has been rhetorically braver – on international debt relief, for instance – it has found itself politically strengthened. The prime minister’s willingness, in his conference address, to put the case for choice in public services in terms of extending to the under-privileged the opportunities long enjoyed by the middle classes was, perhaps, a signal that this lesson is being learned. It was certainly the strongest case he has made for this policy, as was his contention that the failure to reform public services simply entrenches existing inequalities.

It is clear, therefore, that the task of strengthening Labour’s political position is not one subject to simple solutions. However, we believe the party can begin to make an immediate start by honouring its 1997 pledge to hold a referendum on the voting system for Westminster. The case for moving towards a more proportional system of voting – perhaps initially beginning with the Alternative Vote so that electors can at least rank candidates on the ballot paper by preference – has been immeasurably enhanced by the results of the election. Morally, Labour’s claim to be a party committed to democracy, pluralism and a new kind of politics is weakened by its continued support for an electoral system that rewards 36 per cent of the vote with 55 per cent of the seats in the House of Commons. And, while we are committed to extending the principles of choice, diversity and devolution to the public services, we would also like to see them better applied to the political system.

Politically, Labour needs to consider the best way to entrench the social and economic changes that three terms in government allows it to make. Electoral reform would provide the political cement to underpin the progressive consensus that the party is seeking to further over the next four years. The weakness of the Conservative party’s performance in May points to the existence of a progressive majority among the British people. Given the minority support that conservatism in Britain has, only the pernicious nature of the country’s voting system could conceivably allow a right-wing Tory party back into government, from where it could begin destroying the achievements of the past eight years. Conversely, only proportional representation can ensure that the strength of the country’s progressive majority – committed as it is to the kind of changes that Labour is making – is truly reflected in future parliaments.