'Murderball' teams prepare for slaughter as wheelchair rugby gets started at the Paralympics

USA are favourites for the gold, but only narrow margins separate the top teams

"We're ready. Physically we're ready. Mentally we're ready. We're so ready to play we almost want to kill each other." It is a peculiarly apt assertion from Great Britain's Ross Morrison, who will today begin probably the most eagerly anticipated competition of the Paralympics – wheelchair rugby, aka murderball.

It starts at 2pm today, in the Basketball Arena, with Great Britain versus the USA. "30 seconds is all it will take," says Morrison. "Before the crowd are going 'wow!' That's how long it'll be before the first big hit. People won't believe it. They will be, like, 'Oh my god. Are they seriously allowed to do that?'"

The USA will be a tough opponent. They are favourites for the gold medal, but only narrow margins separate the top teams. At 33, Morrison played in Athens and Beijing too. On both occasions Great Britain finished agonisingly fourth.

One man they'll have to stop, if they want to win the tournament, is Ryley Batt. The Australian is only 23, but playing in his third Paralympics. He is the standout star of the sport.

Ryley is a 3.5. Depending on how much use a player has of their arms and upper body, they are awarded a score from 0.5 (least mobility) to 3.5. Teams are 12-strong, with only four on court at any one time. Whichever four are on court must not have a combined score higher than eight.

Aaron Phipps is the only 3.5 in the GB team.They're a big investment but they can be unbelievably dominant.

In terms of how it is played rugby is a bit of a misleading term. It is more like basketball, only it's full contact, you don't have to bounce the ball, and you've simply got to get the ball over the opposition's goal line – and not get murdered in doing so.

You're not allowed to try and spin someone's chair from behind, but apart from that, it's open season. Great Britain's captain, Steve Brown, was once hit with such force he came out of his chair and broke his sternum and six ribs on an opposition player's knees. There are eight teams in competition, divided into two groups from which the top two qualify for semi- finals, then the final on Sunday, among the last of the medals to be awarded.