There are several schools of thought on this one.

Traditionally, roses were pruned back by half around now and then taken right back in march

However, some people like to get them pruned and tidied now, although you do run the risk of getting weak growth in mild weather, which will be killed by frosts.

Others like to wait until march and do it all then.

My favourite time is March.

I have just cut mine back by half ,mainly to stop wind rock loosening the roots,and then prune them properly in March too.It just depends on the variety,as Patio types only need a bit of a tidy up,and dead headed..

I do mine (climbers and ramblers) in March before the leaves start - much easier to see what's what. And less to carry away.

I had no second flush on my wonderful 'A Shropshire Lad' this year because I tidied it up too early and got a bit carried away. Meanwhile 'Compassion', which I didn't get around to tidying, is still producing flowers now. Lesson learned!

I stil have some lovely flowers on mine. I will remove anything tall that might suffer wind rock and so the rest in March.

I have just done mine, I like Bloomer cut them back by half now to stop the wind rocking them and loosening the roots, where they are situated it gets very windy, I then cut them right back in March

All the old fashioned gardeners in the media, eg Percy Thrower, Geoff Hamilton, Geoffrey Smith as well as the RHS would have told you that late Feb to early March is the best time to prune bush roses like Hybrid Teas or Floribundas, Climbing roses tend to be pruned in late autumn, but I see no reason not to do the same as for bush roses. The problem with pruning now is that in a mild spell roses tend to put on a little growth which are then killed by frost followed by die-back which can kill off whole stems over winter.

Many people prune their roses now including parks depts because it looks tidier. But in a severe winter a lot of die-back of the stems makes it seem less of a good idea.