THREE people were arrested yesterday by detectives hunting animal rights extremists behind a letter bomb terror campaign.

Two men and a woman were taken into custody after a massive police operation involving five forces.

At the same time, three more suspected bombs - one of them destined for an address in North Yorkshire - were seized.

The breakthrough came 12 days after the man leading the hunt, North Yorkshire's Deputy Chief Constable Peter Walker, made a direct plea for help to other animals rights supporters.

Twelve nail bombs have been sent through the post to addresses across the North since December and three people have been injured, including a six-year-old girl.

The most recent attack was last week when an agricultural business in Thirsk was targeted. Suspicious staff contacted police and the device was destroyed.

Yesterday, following an intensive investigation, police swooped on an address in Crewe, Cheshire, and held a 26-year-old man.

Shortly afterwards a 31-year-old woman and a 36-year-old man were arrested at addresses in the Crewe area.

All three were being questioned in connection with explosives offences against the animal industry.

Suspected letter bombs addressed to premises in North Yorkshire, the West Midlands and Wiltshire were intercepted by police and made safe by an army bomb disposal team.

Since the terror campaign began three months ago, the targets have varied from farms and charities to pet shops and agricultural firms.

Targets have included an agricultural suppliers at Masham, where the bomb did not explode, and a farm near Ripon, where a man suffered facial injuries.

At an estate agents in Patrington, East Yorkshire, an explosion left a woman employee with severe facial injuries and she is still waiting to discover if she has been blinded.

And at Congleton, Cheshire, a six-year-old girl received leg injuries during an explosion at a pest control business.

Other targets have included premises in Newcastle, Sheffield, and Penrith. Not all the bombs have exploded.

The North Yorkshire force has led the investigation, which also involved teams from the Cheshire, North Mercia, South Yorkshire and Metropolitan forces.