Without fptp there would be no Labour party

No party can claim to be for small government if it endorses fptp. Even if the party of the centre-right is for small government in all of its other policies it is still promoting big government if it supports fptp. This is because fptp 'forces' the voter to choose between only two political parties. Even if one of those parties is for small government reducing the choice like this is a problem. Assuming the voter wants small government introducing pr will make no difference because that choice will remain. If the voter wants (requires) some government at all then restricting choice will encourage them to shift to the party of big government. If the voter is not an anarchist then more choice is better. This way they can get the government they want without sanctioning more of it. Pr enables voters to be selective about the extent of government they want. It is not good to force people to choose between no government and huge government.