A memorial service to mark the 42nd anniversary of the M62 coach bomb that killed 12 people will be held at Hartshead Moor service station.
On Monday February 4, 1974, a 50lb IRA bomb ripped through the coach carrying service personnel, their wives and families along the M62 between Birstall and Birkenshaw, reducing the vehicle to a twisted heap of metal.
Twelve people - nine soldiers and three civillians - were killed by the bomb, which consisted of 25 pounds (11 kg) of high explosive hidden in a luggage locker on the coach.
Hartshead Moor was used as a first aid station for those wounded in the blast and has since become the focal point for those wishing to honour those killed and injured.
In 2009 a permanent memorial was created outside the service station and each year it hosts a service to mark the anniversary.
The Mayor of Calderdale Councillor Lisa Lambert will be attending the event on Sunday at 10.15am at the motorway services.