On February 4, 1974, the district’s residents woke to news that a coach carrying servicemen and their families had exploded on the M62 motorway near Hartshead Moor.

A special early edition of the Telegraph & Argus reported that 11 people had been killed and 14 injured when a bomb reduced their 56-seat bus to a tangle of twisted metal earlier that morning.

The death toll from the suspected IRA bomb later rose to 12, comprising eight soldiers and four civilians. Two boys, aged five and two, were among those murdered.

In the immediate aftermath, the dead and injured were strewn over a 100-yard stretch of the motorway and Hartshead Moor service station was soon transformed from being just another rest-stop to a makeshift hospital and temporary base for the police investigation.

Following the explosion, which could be heard several miles away, a plaque bearing the names of those killed was put up at Hartshead Moor to offer the victims’ families a place for remembrance and quiet reflection.

Terry Griffin, a 24-year old soldier from Bolton, was one of those killed in the blast and twice a year, on his birthday and on the anniversary of the incident, his younger sister Maureen Norton lays flowers there.

But on her last visit, Mrs Norton was horrified to find she could not get near the plaque because the area around it was packed with service station customers.

It used to be located on an outside wall but 20 years ago, when the building was extended, it found itself inside the busy foyer.

“You can’t just stand there and have a quiet moment of reflection, it is such a busy area,” said Mrs Norton, who contacted the service station to mention the “disrespectful” treatment of the monument.

This week, bosses at Hartshead Moor, which is operated by Welcome Break, revealed that a more fitting memorial would be created in an appropriate location – a memorial garden – outside the building.

And the memorial will be ready in time for an official rededication ceremony on the 35th anniversary of the tragedy – February 4 next year.

Andy Jagger, Hartshead Moor site manager, told the Telegraph & Argus how the decision had come about.

He said: “Just inside the front door of the service area, we have got a memorial plaque to the victims of the M62 bus bomb that happened in early 1974.

“The plaque has been there for about 33 or 34 years and originally it was outside the front door. Over time, redevelopment and refurbishment have meant that the building has got bigger and the plaque has ended up inside the building.

“Two or three months ago, one of the relatives of somebody who tragically died in the bomb made contact asking if it would be possible for some shelving or something similar to be put around the plaque so cards and flowers could be placed there on anniversaries and Remembrance Day.

“At that point I made contact with the relative, Maureen Norton, and asked if we could meet to look at other alternatives because, in my opinion, as the guy who runs the place, it is not in an ideal location.

“There’s no space there for anybody to reflect. It is in a place where we sell goods nearby, there’s machine noise, and customer traffic noise. So we started the process of proposing that we have a new memorial or a re-siting of the old memorial to the exterior of the building on a lovely green area where we would have a monumental stone with the plaque and a memorial garden. It would be an area for reflection more than anything.

“With Maureen’s help, it looks like we have got the support and interest of most, if not all of the families – certainly those who we’ve managed to track down.

“We have got the Royal British Legion involved from Manchester and from this side of the Pennines in Yorkshire. The bus originally set off from Manchester so there’s really strong ties with Manchester and Oldham and that part of the world.

“We are progressing to what’s looking like the 35th anniversary next year when we will have a new monument and a rededication ceremony.”

Mr Jagger revealed how the incident had “cast a dark cloud” over the service station and its staff for many years. He said: “The actual incident happened out on the M62 about three quarters of a mile down the road towards Chain Bar.

“Hartshead Moor at the time and this carriageway was used as the clearing station, for want of a better phrase, where the emergency services, the military, the injured and I’m afraid to say, the people who lost their lives, were brought before being moved on to other places .

“It was incredibly significant and I have still got a team member working for me here who was working at the time and although a lot of time has passed, people in the area still remember the night.

“We just want to give it the respect it deserves. It will be good for all parties.”

The IRA never claimed responsibility for the bomb. Later in 1974, Judith Ward, a 25-year-old Stockport woman, was convicted of murdering the 12 people who died in the coach bombing.

But she was released from prison when the conviction was quashed on appeal in 1992.

No-one has been charged with the bombing since and, under the terms of the Good Friday peace agreement in Northern Ireland, it is thought unlikely that anyone ever will be.

The coach had been specially commissioned to carry British Army and Royal Air Force personnel on leave with their families to several bases, including Catterick, during a period of industrial action on the trains.

e-mail: will.kilner @telegraphandargus.co.uk