How hard can you prune a fig tree back without killing it?

I think they can be quite hard pruned, certainly one my mum has, had to have severe work done to it and it sprouted away really well from heavy wood. On that basis, I would say yes though the fruiting will probably be set back a good season or two, at least on the parts you prune heavily.

If on the other hand there are many newer and lower stems, these may still fruit for you whilst the others you prune will only make growth at least as said above for a year or two.

If I was going to prune, I would probably do it in late winter, several weeks before the new buds start to swell.

Hmmm! Definitely select stems and reduce the tree over a season or two. Look at this link:

http://www.rhs.org.uk/advice/profiles0103/fig.asp

I am really brutal when pruning my fig tree and it never fails to produce fruit year after year. In late summer I just prune back the leaves that stop the sun getting at the ripening fruit, and then later hack it into shape. It comes back smiling.I live in Gwent
t and it is against a sunny wall and sheltered.