This could be the conclusion to the Labour Party's 2015 manifesto:

Labour's Call to all Progressives

Quite a number of political parties will be taking part in the coming Election. But by and large Britain is a country of two parties.

And the effective choice of the people in this Election will be between the Conservative Party, standing for the protection of the rights of private economic interest, and the Labour Party, allied with the great Trade Union and co-operative movements, standing for the wise organisation and use of the economic assets of the nation for the public good. Those are the two main parties; and here is the fundamental issue which has to be settled.

The election will produce a Labour Government, a Conservative Government, or no clear majority for either party: this last might well mean parliamentary instability and confusion, or another Election.

In these circumstances we appeal to all men and women of progressive outlook, and who believe in constructive change, to support the Labour Party. We respect the views of those progressive Liberals and others who would wish to support one or other of the smaller parties of their choice. But by so doing they may help the Conservatives, or they may contribute to a situation in which there is no parliamentary majority for any major issue of policy.

In the interests of the nation and of the world, we earnestly urge all progressives to see to it - as they certainly can - that the next Government is not a Conservative Government but a Labour Government which will act on the principles of policy set out in the present Declaration.

Actually, it was the conclusion to the 1945 manifesto.

I offer it out of curiosity, not as an endorsement for anything Labour might say in 2015 - because I still have no real clue as to what that might be.