Britain's Alistair Brownlee won a brilliant Olympic triathlon gold as younger brother Jonny took bronze.

The elder Brownlee, injured for the first half of the year, went away on the 10km run and crossed the line with a union jack draped over his shoulders to delight a huge Hyde Park crowd.

It was Great Britain's 19th gold medal of these London Olympics.

Jonny had incurred a 15-second penalty for mounting his bike too early in transition one and had to take it at the end of the penultimate run lap.

That cost him any realistic chance of a fraternal one-two, but he dug in over the last 2.5km to hang on for a gutsy third, behind Spain's Javier Gomez in silver.

At the finish, Jonny collapsed across the line and was given immediate medical treatment in the shelter of the main stands, before being taken away in a wheelchair to put the medal ceremony on hold.

Alistair has been the dominant triathlete of the last three years when not injured, but his Olympic dream seemed in doubt when he tore his Achilles at the start of the year.

"The race was unbelievable and the crowds were amazing," he said. "My ears are still ringing from all that noise.

Analysis British triathlete and current Ironman world champion Chrissie Wellington hails Alistair Brownlee's success following his injury battle "It is incredibly impressive. Not only would it have been physically difficult to train but mentally he will have been riddled with self-doubt. It is never easy struggling with an injury and that is what makes this victory all the more impressive. He even had a pool installed so he could aqua jog and do some of his training in the water." Watch the 1500m Serpentine swim again Watch the 43km bike ride again Watch the 10km run again

"The pressure was stacked up and so many things put to bed today.

"It feels a bit underwhelming because Jonny has collapsed, but, no, it is fantastic. I am massively proud of Jonny."

Alistair only returned to World Series racing in Kitzbuehel last month but wound up the pace to burn off 2010 world champion Gomez in ruthless fashion.

Four years ago in Beijing, as a callow 20-year-old, he had led for three laps of the run before blowing up and finishing down in 12th.

This time there would be no repeat. Gomez stuck to his heels as long as he could but was stretched and stretched until he snapped.

Both Brownlees came out of the 1500m Serpentine swim in a lead group of five that also included Gomez, with third Briton Stuart Hayes just a few seconds back.

Jonny then made an error by mounting his bike too early and so incurred a 15-second penalty.

That group of five built a lead of around 20 seconds after the first bike lap of seven but were then closed down as a large group came together with four laps left.

All the big guns were in that lead pack coming into transition two, meaning the battle for medals would come down to the 10km run.

The brothers went off hard, taking Gomez with them as a small gap immediately opened up, and for the first two laps around the lake the three stayed together.

The younger Brownlee was the first to drop off, before Gomez capitulated as Alistair wound the pace up relentlessly from the bell.

Brownlee's 10km run split of 29 minutes and seven seconds was only just over a minute and a half slower than Mo Farah's gold medal-winning time in the track 10,000m last Saturday and only a second off the second-placed Briton in that final, Chris Thompson.

Although that comparison is slightly unfair on Farah - his personal best in the 10,000m of 26 mins 46.57 secs is considerably faster than he needed at the Olympic Stadium - Brownlee jogged the final 200m here, walking across the line as he soaked up the adoration of the home crowd.