A magistrate manufactured booby-trapped bombs intending to use them against his ex-girlfriend's new lover, a court was told.

Jonathan Wilkes, 40, was arrested after a cache of eight pipe bombs was discovered in woods near his home in Wroslyn Road, Freeland, near Witney, and another was discovered on a wall in Syreford, near Cheltenham.

Each bomb was packed with about 3kg of metal nuts and had the potential, on explosion, to shower a victim with shrapnel.

Simon Mayo, prosecuting, said father-of-one Wilkes, a computer software engineer, had been having an affair with Collette Cooper.

When she broke off the relationship, he began a campaign of telephone calls and text messages begging her to re-kindle the affair and offering to leave his partner, Annie Henriot.

Mr Mayo said Wilkes, a magistrate who had sat on the bench in Bicester, began to harbour "extreme feelings of animosity" against Miss Cooper's new boyfriend, who was not named.

He asked a friend, Andy Kay, if he knew anyone who would be able to "get rid of him", it was claimed.

"Mr Wilkes was trying to find someone who would be prepared to kill Collette Cooper's new boyfriend," Mr Mayo told Oxford Crown Court yesterday.

Mr Mayo said three of the eight bombs found in Freeland, on the Eynsham Estate, contained a booby trap switch which meant they could be rigged to detonate if moved.

They could also be detonated by remote control and Mr Mayo said someone playing with a radio control model could accidentally set them off.

He said: "Make no mistake, these were truly terrifying in their potential to maim and kill."

Mr Mayo said a massive police investigation identified Wilkes as the prime suspect for making the bombs.

Mr Mayo told the jury that Wilkes, then living in St Palais-Sur-Mer, Royan, in western France, told elaborate lies during interviews with police, and claimed he was being blackmailed.

Mr Mayo said Wilkes claimed the blackmailer demanded £50 a week, threatening to tell Wilkes' partner of the affair. The demands then rose to £100 a week and Wilkes was forced to buy electronic components.

Wilkes admits making the bombs but denies two charges of unlawfully possessing explosive devices with intent to endanger life and two charges of unlawfully possessing explosive devices.

The trial continues.