Mainly used by Royal Marine Commandos and Paratroopers, the Sten gun was a useful close quarter submachine gun although it suffered from jamming problems. Allied troops often preferred the Thompson submachine gun (the 'Tommy gun') as their automatic weapon of choice.
The Bren gun was a highly accurate infantry support weapon, however, it suffered from a relatively slow rate of fire and a small magazine. It was still a very useful weapon and was used by commonwealth forces in all theaters of WWII. It was very similar to the American Browning Automatic Rifle (BAR) but had the advantage of a top loading magazine. This allowed the gunner to change magazines without moving the gun off target too much.
The British equivalent of the American 'Bazooka', this 'personal, infantry, anti-tank' (PIAT) weapon only had a useful range of about 50 yards!! It was also inaccurate and it's spring loaded mechanism often jammed. It wasn't much good against Panzer mark III's or IV's and was certainly no match for the later German heavy tanks like the Panther, the Tiger and the King Tiger, indeed, allied soldiers recalled how they would watch the projectiles simply 'bounce off' the armour of these monsters 'without even making a scratch'.