[MasterGunner01]

OK, former UK Security Minister Admiral Lord West, riddle me this: If you are a Muslim Jihadist, where exactly do you get your arms and ammunition?
Answer: You get them ILLEGALLY. Usually the suppliers of the ILLEGAL weapons also supply them with the ammunition (and explosives).
What your Muslim Jihadist does not do is buy his ILLEGAL weaponry and ammunition and explosives at your local UK convenience store, hardware store, or gun shop.
It may come as a complete surprise, Admiral Lord West, that the UK has a lot of ILLEGAL guns cached about your insecure little island.
Question: How are you going to defend yourself when the Muslim Jihadists come for your head, eh?

[Ajnin]

I’m sure you can’t just go to the local Le Walmart and pick up rockets and grenades, but that didn’t stop the 7th century sheep shagging sand goblins from getting their hands on ordnance.

[Gritty]

Wouldn't it just be more effective simply to ban Muslims?

The country would be a much more pleasant and civilized place, too - sort of like in the Old Days before the Koranimals came in, took over, and turned the country into an open-air insane asylum.