Thirty-three-year-old Eric Malcolm wrapped a live 240-volt extension cable round a door handle and waited for his victim Tony Gilesnan to walk in, the Daily Express reported.

Gilesnan, luckily, received only a mild shock but Malcolm then struck him over the head with a hammer, Cambridge Crown Court was told.

Their row about the TV bill had escalated after Malcolm mistakenly thought the lodger had used his computer.

Malcolm, of Royston town in Hertfordshire county, admitted causing grievous bodily harm before the court.

Prosecutor Rebecca Smith said the lodger was left with a three-inch cut to his head after the attack that was carried out April 28 this year.