They are renowned for their self-discipline and respect for authority in some of the most dangerous conflicts around the world. But it appears that, when Britain's fighting men are playing at home, the sense of fair play can desert them.
Rugby and football teams run by the Ministry of Defence have been warned about their future conduct after a sharp rise in sendings-off and cautions over the past few years.
The Army's rugby set-up, which has traditional links with the professional game through international players that include Will Carling and Josh Lewsey, has seen an increase in the most serious disciplinary problems in recent years. Seven players have been sent off this season – three for the dangerous "spear tackle", where an opponents is lifted into the air and dumped on his head. In total, the Army has recorded 41 red cards shown to rugby players over the past four years.
And the number of cards dished out to footballers soared from 578 to 712 last season alone, with the toll of red cards rising from 57 to 87. Players have been hit with fines and bans lasting up to five weeks at a time.
The expulsions are spread across all military units and cover offences from stamping and spitting to general "unsporting behaviour".
But most worrying for defence chiefs are the incidents of dissent and violent abuse directed at match officials. A series of referees' disciplinary reports obtained by The Independent on Sunday reveals that officials have been targeted with foul-mouthed accusations that they are cheats, idiots – and worse.
Former military officers last night lamented the discipline problems on services sports fields – and claimed that the armed forces should set themselves apart from the "loutish behaviour" seen from civilian teams.
"As a commanding officer, sport was always very important because it encouraged teamwork and allowed you to beat other units," said Clive Fairweather, a former SAS officer. "But we always played in a gentlemanly way. Bit by bit, modern life has crept in... and I'm not sure sports are played in the correct spirit any more."
The RAF, too, has documented a series of incidents on the rugby field, including fights, punches, and a player sent off for stamping on an opponent's head. A referee reported booking a player who told him, "That's a fucking joke", only to send him off three minutes later for following up with: "That's fucking bollocks, ref!"
The official services disciplinary records show army football teams have received more than 2,700 cards since 2007-08 – including 405 so far this season. On an afternoon last December, a football team from 2 Para was reported for "multi-player misconduct", picking up five bookings and two red cards in a single match.
The RAF Football Association documents a series of suspensions, including one after a referee was called "a fucking idiot". In another post-match report, an official declared: "After the final whistle, the player who had been sent off earlier in the game looked at the referee and mouthed the word 'wanker' while gesturing the same with his hand." The player, from RAF Brize Norton, was fined £25 and banned for 35 days.
Patrick Mercer, a former army officer and now a Tory MP, said: "I would hope that the armed forces' teams would stand above some of the loutish behaviour we have seen from civilian players."
An MoD spokesman last night said: the armed forces expected "the highest standards of sporting behaviour to be shown at all times".