The Conservatives are hurtling towards catastrophe over Europe

Amid threats of disruption from Jeremy Corbyn's friends in the trade union movement, the Conservative Party Conference is under way. But already the Daily Telegraph interview of the Defence Secretary, Philip Hammond, has brought out the incoherence of policy towards Europe.

His threat that the British people might vote to leave the EU was promptly undermined by his assertion that it would be "economically damaging" to do so, making it plain that, however little the renegotiation achieves, he would campaign to stay under the rule of Brussels. Mr Cameron, meanwhile, seemed much more ready in his own interview to contemplate leaving the EU.

I will not be in Manchester, having lost my taste for my party's Conferences — not so much from memories of the efforts of Mr Corbyn's friends to murder Margaret Thatcher and her colleagues at The Grand Hotel, but because what was once an event for grassroots party members to interact with their leadership is now a media and public relations event at which they are tolerated but given little chance to participate.

Naturally enough, I wish Mr Cameron and his colleagues well, but I am concerned at an air of smugness about prospects for the election of 2020.

All too many Conservatives can scarcely conceal their glee that the Labour Party should have elected a leadership tainted with neo-Trotskyism, antisemitism, sympathy for to terrorism, and neo-Marxist economics.

They think it unlikely that such a leadership will be attractive to very many voters and they are almost certainly right about that, but it does not men that traditional Labour voters will stay at home to watch a triumphal Tory Party sweep the board in the General Election of 2020.

The Tories should not be too smug. Too many of the party's leadership seem to have forgotten that Mr Cameron's victory in May was not built on a huge surge of support for the Tory party (which polled only 11.3 million votes). It was Labour's wipeout in Scotland at the hands of the SNP and the collapse of the Lib Dem vote in England which gave Mr Cameron his majority.

Neither of those should give comfort to the Conservatives. In Scotland the flight of Labour voters to the SNP was a protest against the Westminster establishment of professional careerist politicians remote from their electorates. That will not change to the Tories' advantage. In England Lib Dem voters were turned off by the participation of their Members of Parliament in the Coalition, which tainted them in the eyes of their former supporters. By 2020 they may well have got rid of that taint, recovered their former supporters and set out a stall to capture former Labour voters repelled by Corbyn.

All that apart, it seems to me that there may well be a couple of political asteroids which could strike with catastrophic effects on the Tory party before 2010.

Just as in Thatcher's time, two of them are the leadership succession and our relationship with Europe. The second volume of Charles Moore's monumental biography relates how destructive they can be.

Wisely Mr Cameron concluded some time ago that he should not seek a third term as Prime Minister, but in saying so he opened the season for a succession battle. Rather less wisely, he thought that he could close down arguments about the European issue by announcing that he would "renegotiate" our place in the EU and hold a referendum in which he would campaign for continuing membership by 2017.

Mr Cameron cannot be blamed for failing to foresee the crisis caused by the invasion of western Europe by migrants from areas being devastated by the Muslim religious civil wars. However he should have foreseen the inevitable economic and political crises inherent in the attempt to force the pace of political union by imposition of a single European currency without a single European Treasury, tax and expenditure rules.

The Greek tragedy has not been averted; it has simply been prolonged. The case for Brexit becomes stronger every day, while the prospects of a referendum campaign in which the Conservative Party is united diminish.

At least the remarkable rise of support for Ukip has been arrested. As at critical moments before in the history of Goldsmith's referendum movement and subsequently in the early 1990s of Ukip, dissident members of the party once again seem intent on its destruction.

Still, the new Conservative leadership may have to decide betweeing losing Europhile supporters to the Lib Dems or losing Eurosceptic voters to a resurgent Ukip.

What other political asteroids may emerge from space in the next four years? Well, Zac Goldsmith for sure!