3 successful attacks. A large number have been thwarted. Also you think they need training from the IRA? You want more successful attacks? WTF?
Your sarcasm detector turned off?
A large number of IRA attacks were thwarted as well, hence the glib comment about needing some better training.
The reality is the number of successful attacks on the UK since the Good Friday agreement has gone down dramatically. Whether that be because of the work of the security services, less organised terrorism, or a lesser actual threat we are unlikely to ever really know.