The confused alibi constructed by Jonathan Wilkes' mirrored character contradictions and disarray in his personal life.

He had a long-term partner, Annie Henriot, with whom he had a son, Vincent.

Former colleagues described him as an intelligent, pleasant man, who had a good job and liked adventure.

Wilkes took three science A-levels and began a bio-chemistry degree before dropping out. He returned to university to study computer science and became a computer programmer.

Virgin Atlantic aircraft captain and friend Paul Whelan said: "He is an intellectual guy. One of the reasons we met and had conversations was because he was a pleasant person to talk to, well-read and intelligent."

He was also a member of a paragliding club, Xclent, which flew from a field close to Syreford, Gloucestershire, where the first bomb was found.

But Wilkes, who earned £100,000 in 2000, also had a secret and desperate side to his character.

He had an affair with former work colleague Collette Cooper, and was prone to fits of jealousy and rage.

The couple met when they worked at a car leasing firm, in Swindon. By November 1998, when Miss Cooper left the firm, they were lovers.

"He was very intelligent, liked a challenge. He was fun to be with but he later became very possessive and lost his temper quickly," she said.

While he was having the affair, Miss Henriot was working for the European Commission in Brussels and Wilkes would travel to see her and their five-year-old son at weekends. This left him free to pursue the affair with Miss Cooper during the week.

But, when Miss Cooper ended the affair at the end of 1999, Wilkes began sending text and voice messages to her on a mobile phone he had bought for her.

He had also paid her mobile phone and credit card bills.

She said: "I used to turn the phone off. He bombarded me with messages and text messages."

Miss Cooper said Wilkes was very upset and did not want to believe she was finishing it.

"He said: 'I will leave Annie. I will come and stay with you -- we will tell everybody about it'.

"Most of the time he was crying. When he wasn't crying he was shouting."

After ending the affair, she told Wilkes she was going out with a man called Howard Davies.

Wilkes displayed extreme jealousy and told her Mr Davies could not offer her what he could and that Mr Davies was not good enough for her.

She said the calls from Wilkes eventually stopped when she became pregnant to Mr Davies.

"He Wilkes offered to take me and the child in as his -- that we could get a place we could live in.

"It was probably around that time that the harassment calls and text messages stopped."

It was this inability to control his temper, the court heard, that led Wilkes to hatch a plot to bomb Miss Cooper's new lover, Mr Davies.