Why are we responsible?

We have/had a client who has just been made bankrupt by HMRC: a pub partnership- husband and wife.
It's been on the cards for about two years since a tax enquiry revealed they had not been declaring their true takings (never seen that before eh!) The point is that they have been to see solicitors- at £175/hour- who 'suggest' we, as their accountants, are 'negligent'
I have a written statement by the clients at interviews with HMRC admitting all liability so why do folks try to blame their accountant?
If I smoke (I don't) and go to my doctor denying I do, and then am diagnosed with lung cancer, do I then blame my doctor?
I wrote to the solicitor pointing out the facts and got the clients to sign the letter but....
Sometimes, just sometimes, I wonder why I bother.

Gerard Somers