Spence father and sons died trying to help each other

The three men Noel (L), Nevin (centre) and Graham Spence (R) were overcome by gas

A father and his two sons killed in a farming accident at the weekend, died trying to help each other, their family has said.

Ulster rugby player Nevin Spence, 22; his brother Graham, 30, and father Noel, 58, were overcome by slurry gas.

His sister, Emma, was treated in the Royal Victoria Hospital and was discharged on Sunday night.

The accident happened at the family farm at Drumlough Road, Hillsborough, County Down, on Saturday night.

The other family members, Mrs Essie Spence and her daughter, Laura, are said to be deeply shocked.

A book of condolence has been opened at Ravenhill rugby ground for the three men.

Among those who paid their respects at the rugby ground was the Irish deputy prime minister Eamon Gilmore.

He took time out from a planned visit to greet the new Northern Ireland Secretary Theresa Villiers to travel to Belfast and sign a book of condolences.

The match between Zebre and Ulster that was due to be played on 21 September 20 in Parma will be postponed as a mark of respect.

Eamon Gilmore with Robin Cole and John Robinson from the IRFU Ulster Rugby branch

In a statement, grieving relatives said that the families were trying very hard to come to terms with the loss.

"The three men were very close to each other in life, and that love was expressed in their final moments trying to help one another," the statement said.

"The family is being supported and comforted by other family members, friends and neighbours.

"Arrangements for a thanksgiving service for the three is currently under way and details will appear in the press in due course."

Fans began leaving scarves, flowers and other tributes at Ulster's east Belfast ground on Sunday.

The book of condolence will be available to sign until the end of the week and Ravenhill will be open all week from 09:00 BST until 17:00 BST for anyone wishing to leave tributes.

On Sunday, a minute's silence was held at the All-Ireland camogie final at Croke Park, Dublin.

Flowers and tributes have been left at Ravenhill rugby ground

BBC Ireland Correspondent Mark Simpson said: "Initial reports suggested Nevin's father fell into the slurry tank.

"It was reported that one of his sons tried to rescue him, then Nevin got involved, and his sister Emma."

The Health and Safety Executive (HSENI) said two of its senior inspectors attended the scene on Saturday evening.

"From HSENI's initial investigations, it understands that the three family members who entered an underground slurry tank died from the effects of exposure to slurry gases," it said.

"The exact sequence of events is not yet clear but HSENI is investigating a definite line of enquiry."

Slurry is a mixture of cow manure and water which is used as a natural fertiliser on the fields. However the gases generated as it decomposes in slurry tanks, can be lethal.

The most poisonous is hydrogen sulphide which is produced in large amounts in a slurry tank.

Prayers were said on Sunday for the family at Ballynahinch Baptist Church, which the Spences attended.

Rev Rodney Stout said the three men were all "incredibly gentle, decent, hard working, with a deep sense of family loyalty".

He said he visited the Spence home on Saturday night and the family were just beginning to come to terms with what had happened.

He said the tragedy would have a huge effect on a very tight-knit community.

Ulster Rugby's director David Humphreys said Nevin Spence "was a dream player to work with. He was the epitome of what we were looking for.

"On days when nobody else wanted to come in and train, he was there leading from the front.

"All he wanted to do for the remainder of his career was to stay here, win trophies and be successful for Ulster."

Shane Logan, chief executive of Ulster Rugby, said Nevin was "an exceptional young man".

"A man who was killed in his prime aged 22 with an immense future in front of him and we know that because in his 22 years he was a model professional and a model individual," he said.

"A man of absolute integrity, complete determination, great humility, a fine team player and an all-round exceptional individual."

A private service for Nevin's fellow players and friends was held at Ravenhill on Sunday.

"We will do everything we can to help the players cope with this," Mr Logan said.

Nevin was a former student at Wallace High School in Lisburn.

In a statement, the school said: "It is with immense sadness that we learnt of the tragic accident which has taken the lives of three members of the Spence family.

"The loss of Nevin, our much respected former student and a role model for so many young rugby players, his brother, Graham, and his father Noel, is a devastating tragedy."