Wait until it has dropped its leaves and is dormant or the cuts will bleed.

I escape into the greenhouse on Xmas day and do mine. the victorians used to do it at xmas too, though i suspect it was a way of keeping the 'hired hands/staff' in their place. Certainly as mg says do it when dormant but before March.

ive pruned mine ~ had it 2 or 3 years and still no fruit ~ is there any hope?

Don't prune it so early Stickitoffee and if it is a new vine they take several years to fruit.

Some kinds don't fruit with really heavy pruning, either. I would try leaving a few twigs about 40 cm long this year, and see what happens.

oh good ~ thank you ~ luckily thats about what i have done