A man with a grudge against Network Rail has been found guilty of 12 counts of criminal damage and a further charge of arson.

The attacks all took place in the Midlands over a 14 month period from June 2004.

Allan Nicol, 48, had worked as a recruitment manager for a firm that supplied Network Rail. When Network Rail stopped using the firm to recruit staff Nicol launched his first wave of attacks, apparently motivated by a sense of injustice. When he was made redundant a second wave of attacks began.

45 police officers were involved in the 14-month investigation into the vandalism, which included the cutting of line-side cabling at Kingsbury Junction in Warwickshire and a fire in the relay room in Rugeley, Staffordshire.

Network Rail has said the damage led to 5,963 delays and 970 train service cancellations, and cost £4m.

Nicol was caught after being traced from a discarded receipt at the scene of his last attack. He will be sentenced on 7 March at Birmingham Crown Court.