A Welsh rugby player has died after suffering a suspected cardiac arrest during his club's League 1 match at London Skolars, the Rugby Football League has announced.
Danny Jones, a Wales international who was 29 and played for club Keighley Cougars, collapsed after being replaced early in the match and was treated by the match doctor and paramedics at the ground before being taken to the Royal Free Hospital. Despite extensive efforts to resuscitate him, Jones passed away at the hospital.
RFL chief operating offficer Ralph Rimmer said: "It is always devastating when someone so young dies in these circumstances.
"Danny was a popular and talented rugby league player, having played at the highest level with the Wales national team and over 12 seasons for Keighley Cougars and Halifax."
Rimmer added: "The rugby league community will mourn his loss and I wish to extend our deepest sympathies to Danny's family and friends at this incredibly sad time.
"The family, friends and team-mates of Danny are currently, and will continue to be, supported by the RFL Benevolent Fund and Sporting Chance.
"We would ask that the privacy of the Jones family, players and Keighley Cougars staff be respected."
Jones was taken off after only four minutes of the match at the New River Stadium on White Hart Lane after apparently complaining of feeling unwell. An air ambulance was called and he was taken by road to the Royal Free Hospital in the capital and the game was abandoned.
A London Ambulance Service spokesperson said: "We were called at 3.10pm today to an address on White Hart Lane.
"We sent a number of resources, including London's Air Ambulance and two ambulance crews to the scene.
"The patient - a man - was in cardiac arrest."
Jones, who was in his second spell with Keighley after also playing for Halifax, made his Wales debut against Italy in 2010 and won the last of his 12 caps in a World Cup group match against Cook Islands in Neath in November 2013.
Wigan forward Ben Flower, a team-mate during the 2013 World Cup, led the tributes.
Flower tweeted: "My thoughts are with Danny's family. Worst possible news. What a great man and even better friend. He will be missed so much. #RIPDannyJones."
Wales RL tweeted: "All at Wales #rugbyleague would like to send our condolences to the family and friends of Danny Jones after his sad passing today."
A spokesman for the players' association League 13 said: "Our deepest sympathy and condolences go to the family of Danny Jones tonight."
Jones, who leaves a wife, Liz, and five-month-old twins, was described as the "life and soul of the dressing room".
Keighley issued a statement saying: "Danny was much loved and highly respected by all at the club and in rugby league.
"He was the life and soul in the dressing room, a natural leader, a true professional and irreplaceable.
"He achieved over 1,000 points and 150 appearances for Keighley Cougars and he will be sorely missed.
"He sadly passed away today at the age of 29, leaving his five-month-old twins and wife and family. Our hearts go out to Liz, his children and his family."
Jones is the second rugby league player in just over six years to die after collapsing during a match.
Wakefield forward Leon Walker, who was 20, fell ill during a Wildcats reserve game with Celtic Crusaders in Maesteg in March 2009. It was later discovered that he had an undiagnosed heart defect and a coroner ruled that he died from natural causes.
Just six months before then, Wakefield's Cook Island international Adam Watene, 31, died after collapsing during a training session in October.
Leeds half-back Chris Sanderson died on the pitch in a match in 1977.