you can cut it back as hard as you need too. I personally would do it in spring. though you can reduce some of it in the autumn if you need too.

many thanks for that

I chopped mine right down to the soil a few weeks back as it was in such a sorry state. The bottom was woody and bare, the leaves were sparse, powdery and spotty, the flowers were all disfigured, so I gave it 'the big chop' hoping to kill it (I couldn't get the root out). Anyway, it is now growing back and looks as if it's going to be a fine specimen. So I think it's safe to prune it as hard as you like, when you like!

Done the exact same as Sheilar with one of mine day before yesterday....I'm confident it will come away again!

Best to leave really hard pruning till early spring - the last thing you want is to force lots of new growth in the next few weeks because you've hacked it right down - it won't be ready for the winter and the plant will suffer. You can, though, as Seaburngirl suggests, take some off now, but make it less than a third.

Franella...please do follow Seaburngirl and Bamboo's advice. Their instructions are how to do it properly.
I didn't mean to mislead you with my advice. I had to cut mine right back as I needed to fix the trellis on which it was attached and if I hadn't it would have fallen and damaged a whole lot more that the Honeysuckle :)
I probably should have made that clear.