Chris Wynstanley (32) told jurors his brother-in-law James Baigent had called him on a Friday or Saturday evening in November 2006 and asked to borrow the trenching tool he used when "war gaming".

Mr Wynstanley, who described himself as "Army barmy", had agreed but said his friend had been vague when he asked what it was for.

He said: "Initially he said 'I can't tell you'. I pushed a bit more and he said 'if I tell you, I'd have to kill you'."

Mr Wynstanley said that was an "army-type joke".

James Baigent (30) and his younger brother Mark (27) later turned up at Mr Wynstanley's home in Surrey, Cambridge Crown Court heard yesterday.

Mr Wynstanley said: "I think I said 'what do you want the spade for?' He said 'you don't want to know'. I said 'come on mate, what have you done – hit a cat or something?'. He said 'you know me, couldn't just leave it on the side of the road'."

It is alleged the Baigent brothers bore a grudge against their half brother Andrew Scanlan (35) after he helped convict Mark Baigent of an attempted armed robbery of a post office in 1998. The prosecution say they also blamed him for the death of their mother, Linda in October 2006.

It is alleged they tricked him into travelling down to Surrey from his home in Dickens Street, Eastfield, Peterborough, on November 17.

It is claimed they, along with friend Jeff Woods (36), then killed him, chopped off his head and hands and buried his body on in dense woodland in Aldershot.

Giving evidence at court, he said he had questioned his friend of 20 years when he discovered Mr Scanlan was missing in December 2006.

He said: "I asked him 'that's not what you wanted the spade for?' He said 'no not at all. But if something's happened to him or anyone's done something I'd like to shake them by the hand'."

Mr Wynstanley said James Baigent had only borrowed the shovel for a few days. However his wife, Charlotte, came and collected it on January 3, 2007, the day he was arrested.

Mr Wynstanley also said he got the impression Mr Scanlan was the "black sheep" of the family whose own mother had disowned him in the past.

Mark Baigent, of Medworth, Orton Goldhay, Peterborough, James Baigent, of Sandhurst, Surrey, and Woods, of Bracknell, Berkshire, all deny murder.

Charlotte Baigent (28), of Sandhurst, Surrey, who is alleged to have helped clean the interior of a white Ford Escort used to transport Mr Scanlan to his death, denies three counts of assisting an offender and perverting the course of justice.

The trial continues.