PRIME Minister Gordon Brown was arriving in Northern Ireland today after two unarmed soldiers were shot at their barracks – bravely shielding victims from a terrorist massacre. Mr Brown was being accompanied by Northern Ireland Secretary, Shaun Woodward, and will meet police Chief Constable Sir Hugh Orde and political leaders at Stormont.

Mr Woodward said: “This is really a moment where we have to decide how we secure our future.

“If people come forward, there’s no question... people will go to jail for a very long time.”

Later he will hold talks with First Minister Peter Robinson and Deputy First Minister Martin McGuinness to urge the DUP and Sinn Fein representatives to stand united in the face of the dissident threat.

Britain was last night reeling from the horrific flashback to Ulster’s darkest days.

A pizza delivery boy wounded as masked “Real IRA” gunmen opened fire outside an Antrim barracks told how he was saved by one of the unarmed squaddies throwing himself on top of him.

Domino’s driver Anthony Watson, 19, said in hospital: “The soldiers shouted for us to ‘get down’ before I even knew what was happening.

“Then one of the soldiers just threw himself on top of me as the bullets were still firing.”

A pal told how the teenager — nicknamed Anto — owed his life to the courageous squaddie.

The horrified friend said: “The guy with the gun then just walked over and executed the soldier as he lay on top of Anto.”

Slaughtered Three more shots were also pumped into terrified Anthony.

A fellow Domino’s worker from Poland — who had arrived by chance with a second pizza delivery — was last night fighting for life after being shot SEVEN times.

The two soldiers have not been named but are expected to be identified later today.

They are believed to come from London and the Midlands.

Two of the dead soldiers’ comrades were also wounded in what Mr Brown yesterday branded a “cowardly” outrage.

The last British soldier murdered in Ulster was Lance Bombardier Stephen Restorick — shot by an IRA sniper at a roadblock in 1997.

Two gunmen staged Saturday’s ambush, with a third terrorist acting as getaway driver.

Last night a gang calling itself the South Antrim Brigade of the Real IRA boasted it was behind the carnage.

Along with other IRA renegades they are hell-bent on wrecking the decade-long peace in Northern Ireland by plunging the province back into a nightmare of violence.

Mr Brown vowed as Sinn Fein joined him in condemning the killers: “No murderer will be able to derail the peace process — THAT has the support of the vast majority of the people of Northern Ireland.”

Surgery The soldiers — both in their 20s — were slaughtered minutes before they were due to fly out with comrades to Afghanistan.

They had planned a farewell feast of pizza — and emerged in their desert fatigues from the main gates of Antrim’s Massereene Barracks as the takeaways arrived.

Delivery boy Anthony was hit in the shoulder as the terror gang opened fire with automatic weapons — aiming to mow down him and his fellow pizza worker along with the soldiers.

His pal said: “He felt like he had been punched on the arm. The first bullet just went straight through him.”

As Anthony lay with the heroic squaddie on top of him, gunmen cold-bloodedly unleashed a second volley of shots — then finished off the two fallen soldiers.

Anthony was repeatedly shot by the brute who stood over him.

Last night he was recovering after emergency surgery to stomach and chest wounds.

His mum Joyce — a cleaner at nearby Catholic St Comgall’s Primary School — was at his hospital bedside.

Renegades accuse anyone co-operating with the Army or police of being “collaborators.”

A driver who passed by within minutes of the atrocity told of seeing several bodies including a soldier “spread-eagled in the road with blood pouring from his head.”

He said: “I couldn’t tell who was dead and who was alive.

“There was blood everywhere. It was horrific.”

“It’s shocking to think this could happen in today’s Northern Ireland. I thought we’d left all of this behind and moved on.”

A Toyota Avensis left near the barracks gate was believed to have been used by the gunmen.

A Vauxhall Cavalier thought to have been used in their escape was found dumped in nearby Randalstown.

Cops hunting the gang were trawling through CCTV as forensic experts in white suits combed the scene of the bloodbath.

The two bullet-riddled cars driven by the pizza workers were taken away for examination.

Chief Supt Derek Williamson said bluntly: “This was an attempt at mass murder. Two very young men lost their lives in a very callous and a very ruthless attack.

“The terrorists not only wanted to kill soldiers but also to try to kill those two pizza delivery men.”

He added: “The gunmen, having fired an initial volley of shots, moved forward when people were on the ground and fired additional shots at those on the ground.”

The names of the shot soldiers — members of 38 Engineer Regiment — were being withheld until relatives were informed.

Sinn Fein president Gerry Adams called on Republicans to shop the gunmen.

Desperate He declared: “There is an onus on all of us to work with the police in ensuring that those who carried out the act are apprehended.”

He stressed: “The people who carried out the attack attacked the peace process.

“They are seeking to destroy the gains that have been made. But the time for conflict is over.”

The horror follows a string of failed terrorist outrages over the past two years.

Ulster’s chief constable Sir Hugh Orde had warned the terror threat was worsening.

But militant republicans — including Mr Adams — accused him of making things more fraught by drafting in undercover soldiers to carry out surveillance.

Yesterday as Ulster was left stunned by the soldiers’ murder, Sir Hugh ruled out putting troops back on the streets.

He insisted: “This was an act by an increasingly desperate small group of increasingly desperate people who are determined to drag 99 per cent of this community back to where they don’t want to go.”

The number of renegades active in Northern Ireland is believed to number fewer than 300.

A planned trip to the US for a St Patrick’s Day meeting with President Obama was put on hold by Northern Ireland First Minister Peter Robinson and deputy Martin McGuinness.

The White House was swift to condemn the shootings.

Its Northern Ireland spokesman Robert Wood said: “Our condolences go out to the families of the slain soldiers.

“We call on all parties in Northern Ireland to unequivocally reject such senseless acts of violence.”

Mr McGuinness, a former IRA leader in Londonderry, issued a plea to dissidents to end their savagery — insisting: “The war is over.”

But warped supporters of the killers logged on to an extremist republican website to salute the gunmen.

One message urged: “Keep them coming lads.”

The dead and wounded soldiers had been due to board a flight at nearby RAF Aldergrove to combat the Taliban in lawless Helmand province,

Yesterday the plane took off for Afghanistan with four empty seats.