Why was he allowed to get so far?
Our police are not routinely armed, and an armed response unit did not get there in time.
Of course, until recently, the unarmed police would have intervened.
It was unarmed policemen who confronted the IRA team that bombed and machine gunned Londoners in the 70s, leading to the Balcombe Street siege.
They have become rather more risk averse nowadays.