Hard pruning pyrancatha hedge

I I have an old hedge about 2 m high and 1m wide .

I would like to lower it so it is easier to prune . When and how should I do it ?

Thanks for any help ....... 

It's never a good time to prune pyracantha.

As you realise, during the Spring, the buds and flowers are developing on the wood from the previous year, so, ideally, you want to leave them. And then all through the Summer the fruits are developing, and you want to leave them.

When you talk about a hedge, then perhaps you trim it frequently. Personally, I would not attempt to prune pyracantha using a hedge trimmer. I find that it is best to remove individual shoots, using loppers, or a pruning saw. That also gives you much better control over exactly which shoots you remove.

Two devices which I find quite useful are loppers, and a pruning saw, mounted on an extension pole. Like these:
http://www.amazon.co.uk/s/ref=nb_sb_noss?url=search-alias%3Daps&field-keywords=wolf+loppers+extension

You can get devices like those, from garden centres and DIY stores. They allow you to prune the plant without getting too near to it, and you can easily reach the top without using steps.

As you may be aware, the large thorns on pyracantha are viscious, so you need very strong gardening gloves, and good protection all over.

This is going to be difficult. As you want to lower the whole hedge I think you should just take the plunge and cut the top off, preferably with the strongest longhandled hedgecutter you can lay your hands on and possibly a saw or a long handled chain saw for the thicker stems - a battery one would be OK (that's what I used) - long handled because pyracantha is horribly prickly. Once the top is off so it's lower you can in future trim it as Gary above says. You may well have to cut off a load of berries but never mind they will grow again. Pyracantha is very tough and can be heavily pruned. It's just that it's uncomfortable and dangerous for the gardener when it gets out of control, like mine did! Strong gloves and eye protection needed.

I have a small pyracantha hedge, which I prune all year round.    I just lop it off whenever I have the time and I think it needs it.    I try to cut back to the flowers in the summer, and the berries in the autumn.    It is a tough plant - cut back as often and as much as you like!

Mind those sharp needles!

If you are also plantng bulbs this year, while wearing very strong heavy gloves, put some of the cuttings around the bulbs - it keeps the squirrels off the bulbs.

Pyracantha really does not mind when you cut it, I tend to do it around now - plus the odd bit that I feel is getting away whenever I feel like it.  This year there are very many berries, so the birds will be happy.  Much of the pruning is of new shoots which have sprouted out of the hedge, so you don't lose as many berries as you might think.  I prefer not to do it in the spring as a) there are far too many other things want doing and b) several birds build their nests in that hedge, so best left well alone.   Put on as much armour plating as you can, it really is such a ferocious thing - bit so beautiful in full flower or berry - and so many insects and birds love it. 

Thank you all  for your help ...