As far as arms sales go I'd refer you to the classic episode of 'Yes Minister'. 'If we don't sell them weapons they will only buy them somewhere else.' Added to which munitions producers are generally located in marginal constituencies.

I never agreed with the so called solution to the IRA issue. Blair essentially reduced (did not solve) the problem by giving them what they wanted. I would have stuck with the shoot to kill policy personally but that's just me.

In any case this incident has nothing to do with arms sales and everything to do with psychopathic nutters. The only important thing is that we never give into them regardless of how many attacks they make.