Fifty years ago the 1972 Five Nations Championship was abandoned, left unfinished for the first and so far only time in its history.

Here, former players and rugby officials recall their thinking at the time, while also looking back on the remarkable events of the following year when, in February 1973, England did travel to Dublin.

Delivered to Lansdowne Road under armed protection, they were welcomed by an emotionally charged crowd of 50,000 in “an act of great friendship”.

This story begins on 30 January 1972, when the British Army’s Parachute Regiment shot dead 13 people in Londonderry after opening fire on a civil rights march. The demonstrators had been protesting against a new law giving authorities the power to imprison people without trial in Northern Ireland.

Bloody Sunday will forever be remembered among the most terrible events of the Troubles. In its immediate aftermath, three days later, as some of those killed in Derry were buried, the British embassy in Dublin was set ablaze and destroyed.

The Five Nations of 1972 had opened on 15 January – 15 days before Bloody Sunday. Wales had a strong side, Ireland too. Anticipation among rugby fans was high, but soon the sport was sent into disarray, like so much else.

Ireland began their campaign with victory over France on the outskirts of Paris on 29 January. They would then play England at Twickenham on 12 February.

Willie John McBride, the former Ireland captain, and former British and Irish Lions captain, recalls being accompanied by an armed guard.

He says: “I remember being in London and having protection and asking the guy with me ‘How real is this?’

“He said: ‘We don’t know and we will never know.’ So you lived with that hanging over the top of your head all the time.

“I was getting notes and funny things about what I, a northern Protestant, was doing playing for Ireland, but I just carried on.”

Ireland won in London, the match ending 16-12. With two victories from two, their final fixtures were at home: against Scotland and Wales.

But following what happened at the British embassy in Dublin on 2 February, a nervousness had crept in among the Scotland and Wales camps. After those teams played each other on 5 February – a 35-12 win for Wales – officials from both unions met to discuss whether they would travel to play Ireland.

Scotland’s trip was scheduled first, for 26 February. It was agreed that whatever Scotland decided to do, Wales would follow suit.

When the Scottish and Irish officials held conversations, they focused on safety guarantees for the Scotland players and the possibility of playing the game elsewhere.

There had been offers to the Irish Rugby Football Union (IRFU) to hold the two games on neutral territory. One came from the Belgian Rugby Football Union of all places, another from the French-Inter Celtic Popular Aid Committee based in Lorient, who said they could arrange for the Wales and Scotland matches to be played in the Breton cities of Rennes and Nantes.

Murrayfield was also put forward as a potential venue but the overwhelming response from the Ulster delegates, who at that time dominated the IRFU, was that it was “Dublin or nowhere”.

Another major – but fundamental – issue for the Scots was their struggle to find an insurance company prepared to cover the match in Ireland.

Finally, they decided to pull out – a decision reportedly carried by just one vote. On 17 February it was announced Scotland would not be travelling to Dublin.

Albert Ferrasse, president of the French Rugby Federation, said in reaction: “Rugby has everything to lose and nothing to gain from this.”

Irish rugby certainly had plenty to lose.

Ireland had last won the championship 23 years previously in 1949, and in 1972 had a strong side. By mid-February they and the Welsh looked strongest in the hunt for the title.

Whatever the Welsh Rugby Football Union (WRU) had promised their Scottish counterparts, ambitions of national prestige saw them delay making a final decision on whether to play in Dublin.

Having already beaten England 12-3 at Twickenham, and Scotland in Cardiff, Wales had a chance of winning a second consecutive Grand Slam, which up to that point had only been achieved three times in Five Nations history.

Former Wales scrum-half Sir Gareth Edwards says: “Of course we wanted to play from a sporting perspective, but there were serious matters going on. It was very, very difficult for us to think just about playing rugby. A lot of us were just about getting married, lots of people having children.

“We were very friendly with a lot of the Irish players, we tried get some information from them and asked what they thought – we were very concerned.

“I knew quite a lot of the Irish boys and when we went on tours later on and they’d say: ‘You should have come.'”

British and Irish Lions back Gerald Davies was one of the first Welsh players to announce he would not play in Ireland. He said it would be unfair to his family. Prop Barry Llewellyn then pulled out too, after receiving a threatening letter claiming to be from the IRA.

Wales were due to play in Dublin on 11 March. On 23 February the WRU held a two-hour special meeting. Secretary Bill Clement confirmed they had resolved to meet the IRFU again.

The Welsh were keen to explore the possibility of a neutral venue. But many IRFU officials believed agreeing to it would be interpreted as accepting that Scotland were right to pull out of playing at Lansdowne Road.

After a meeting between the WRU and the IRFU on 27 February, Wales announced that they would not fulfil the fixture. Hopes of another Welsh Triple Crown or Grand Slam ended. Ireland had similarly missed out on championship glory.

McBride says: “The mood was terrible. I can’t remember any game being cancelled because of the Troubles and there had been all sorts of compromises made to keep the game alive. We’d worked so hard to keep rugby union on the ground.”

The two cancelled matches had implications for the IRFU’s finances – with £60,000 in lost ticket revenue (worth about £840,000 today, according to the Bank of England’s inflation calculator).

Irish clubs rallied round to share some of the financial burden by not seeking refunds for tickets bought from the union, and further aid came from France, who played a friendly in Dublin in April, which the Irish won 24-14.

But there was also genuine concern that the Five Nations would be affected for several seasons to come.

The following year, Ireland’s opening fixture was a home tie with England on 10 February. In the weeks leading up to the match, there was great scepticism over whether the visitors would travel to Dublin.

England’s Five Nations training camp was being held in Coventry and the players were still uncertain about what would happen. Winger David Duckham decided to do something. He told captain John Pullin that he was going to make a phone call.

Duckham says: “I said I’m going to ring Willie John. I’m going to just ring him and ask him point blank: ‘Do you think we should come?'”

McBride picked up the phone.

His reply: “I said to David: ‘The first name on the England team sheet is David Duckham. If you cry off the whole damn thing is gone and you could never ever live with that.'”

McBride also made the point that he didn’t consider the England players to be the only ones in danger.

“I said: ‘I’m going to be on the field and if they’re going to get any of us they’re going to get me because I’m a northern Protestant playing for Ireland.'”

This conversation was followed up by a delegation led by RFU President Dickie Kingswell going to see Pullin at his farm on the Gloucestershire coast to tell him they would be sending an England team to Dublin with or without their leading players.

Derry native and veteran sports journalist Peter Jackson observes: “The difference in attitude was that the RFU from the word go said: ‘We will send the team. We will find 15 Englishmen.'”

Security was significant.

Duckham says: “When we came down the steps of the aircraft after landing in Dublin we didn’t go anywhere near the departure buildings. We bypassed all the usual rigmarole that you have to go through and [were put] onto a coach surrounded by armed paratroopers on motorbikes straight to our hotel.”

At the Shelbourne Hotel there were armed guards on every floor and the England squad was instructed not to leave the premises unaccompanied. The Irish team were staying in the same venue.

Duckham recalls: “We tried not to bump into each other, but it was going to happen.

“They brought a film in for us to watch and the door behind me was ajar. I turned as a shadow was cast.”

Standing there was a fellow British and Irish Lions player from the victorious 1971 tour of New Zealand, Ireland’s Fergus Slattery.

“We were good mates and I said ‘Slats, what are you doing here? Go and watch your own film’,” adds Duckham.

“He said: ‘Duckers, our film is absolutely terrible so I’ve come to watch yours.’ And when the film finished he sneaked out of the door!”

The match itself saw one of the most memorable moments in rugby history.

Before kick-off the Ireland team was deliberately held back so that England ran out alone. There followed a huge standing ovation from the crowd that lasted more than five minutes.

A former IRFU president who was at Lansdowne Road that day, Billy Glynn, said; “I looked back at people up in the stand behind me and there were tears on everybody’s faces. And then I realised there were tears on my own face.

“It became an occasion of friendship. I said, this is a great day for sport.”

Duckham remembers it clearly.

“It was such an emotional moment because it caught us out,” he says. “We weren’t expecting the whole stadium to erupt. The loud cacophony of sound. I mean, it was just unbelievably ear splitting.

“And then it all changed when the referee blew the whistle and we kicked off!”

Ireland dominated with two tries scored by winger Tom Grace and centre Dick Milliken that saw them win 18-9. The result was somewhat irrelevant though.

Glynn recalls: “After the match everybody was talking about what happened before kick-off. And people still talk about it today and say ‘I was there’.”

Then there is that famous quote from the England captain Pullin at the post-match dinner: “We may not be very good, but at least we turn up.”

His comment received another five-minute applause.

McBride reflects: “They were horrible days here in Northern Ireland. You just didn’t know when it was going to crop up next. There were murders, there were people disappearing, there was great unrest everywhere.

“They were ugly, ugly years. It was 30 years of my life that really were destroyed and I’m not the only one who could say that.

“It’s something that still stirs up a lot of feeling in some rugby corners that those two games in 1972 were never played. Even outside rugby, people would tell you how disappointed they were.

“Everybody was so keen that England came and we were absolutely thrilled. I think it was very, very important for the whole country.”