I am a member of BALPA and they are far from perfect. I have just looked at the IPA site and to quote:
We also offer legal assistance of £10,000 to our Full members as well as a free legal help line. There is also a facility to top up the Legal cover to £250,000.
If anybody believes that is sufficient (the £250,000 that is) for anything except that which is not major is living in cloud cuckoo land.