Just found this about New self defence laws 2008.
Think the last one may have been a bit OTT
In practice, householders are seldom prosecuted if they harm or even kill an intruder but the Criminal Justice and Immigration Act 2008 will give them greater legal protection.
In one recent case, two burglars broke into a house armed with a knife and threatened a woman. Her husband overcame one of the burglars and stabbed him. The burglar died but the husband was not prosecuted. The other burglar was convicted.
However, in another example cited by the justice department, a householder was prosecuted after he laid in wait for a burglar who tried to break into his shed and shot him in the back.
Another man was deemed to have used excessive force and prosecuted after he caught a burglar, tied him up, beat him up, threw him into a pit and set fire to him.