Image caption David Black was murdered on his way to work

The family of a Northern Ireland prison officer murdered as he drove to work has been left "absolutely devastated".

David Black, 52, from Cookstown was attacked on the M1 motorway at 07:30 GMT as he drove to HMP Maghaberry. Dissident republicans are being blamed.

It is the first time in nearly 20 years that a member of the Northern Ireland Prison Service has been murdered.

The Black's family minister, Rev Tom Greer, said his family has appealed for no retaliation "from any quarter".

"David's wife Yvonne is broken by the loss of her husband," he said.

"His children Kyle and Kyra are in a state of shock and are unable to comprehend what has happened, the brutal murder of their father."

Mr Greer, from Molesworth Presbyterian Church, said that Mr Black was a man who had a "great sense of humour" and was "devoted" to his family and aged parents.

"He was also a guy who was a friend to so many people in this community," he added.

It is the second tragedy to strike the family in the past year. In November last year, Mrs Black lost her father in a slurry tank accident at his farm in Maghera.

The head of the Northern Ireland Prison Service has said no prison officer has been told recently that they are to lose their personal protection weapon.

Image caption Mr Black's car veered into a ditch

Sue McAllister was responding to claims made in the aftermath of the murder. Speaking on BBC Northern Ireland's The View, the Director General said that she was determined to ensure the safety of all prison officers.

"I have checked and to my knowledge no prison officer has been told that his or her personal protection weapon is to be withdrawn," she said.

"I will certainly be making sure that any prison officer who wishes to have a personal protection weapon will be able to apply to the police service as per our procedures."

Mr Black was attacked on the motorway between Portadown and Lurgan.

A car with Dublin registration plates drove up beside him and fired a number of shots. His car veered into a ditch.

Assistant Chief Constable Drew Harris said he sustained very serious and probably fatal gunshot wounds.

The car with Dublin registration plates was later found burned out at Inglewood, Lurgan, County Armagh.

There has been widespread condemnation of the murder. Prime Minister David Cameron said the Westminster government would do whatever it could to help the Police Service of Northern Ireland (PSNI) bring the killers to justice.

"First and foremost this is a dreadful tragedy for the family and friends of David Black who has been so brutally murdered as he went about his work keeping the people of Northern Ireland safe," he said.

"My heart goes out to them. These killers will not succeed in denying the people of Northern Ireland the peaceful, shared future they so desperately want."

Analysis There is a sense of shock at the first killing of a prison officer in Northern Ireland for almost 20 years, but not surprise. Prison officers have been under threat from dissident republicans for a number of years now. There has been a general threat as well as specific threats against some individuals. A number have had to move home under a government funded scheme after being informed that dissidents were monitoring their movements and they were being targeted for possible attack. David Black is not believed to be one of those who had been warned. Read more

On Wednesday, NI Secretary Theresa Villiers, told a Westminster committee that the level of threat from dissident republicans in Northern Ireland remained "severe".

However, she said the number of attacks so far this year was slightly down on the same period last year and that their "sophistication and potency" were on the whole lower.

First Minister Peter Robinson said those responsible for Mr Black's murder were "flat earth fanatics" and "deviants".

He added that the murder would only serve to galvanise and unify the community and its leaders.

Deputy First Minister Martin McGuinness unreservedly condemned the murder and said those responsible could not kill the peace process.

He said there was an onus on what he called the "mouthpieces" who sometimes speak for these groups to come out to explain the rationale behind "this pointless and futile killing".

PSNI Chief Constable Matt Baggott said the killing was a "completely senseless attack" and the victim was "brutally murdered".

Mr Black's murder was also condemned by the Orange Order. He had been a member of Montober LOL 661, a lodge based in Cookstown.

Mr Black was a very experienced prison officer and had worked through the Troubles.

He was one of hundreds of officers who had applied for the prison service redundancy scheme. His application was under consideration and he was awaiting a decision.

Mr Black was the 30th prison worker to be murdered since 1974 in Northern Ireland.

The last prison officer killed was Jim Peacock who died on 1 September 1993.

Loyalist paramilitary gunmen from the Ulster Volunteer Force (UVF) sledgehammered their way into the Peacock family's Joanmount Park home in north Belfast and shot him dead.