Rest a little easier British fans.

The Team GB athlete off his bike and looking concerned is neither Alistair nor Jonny Brownlee, but their team-mate Gordon Benson.

He was back in the main pack and has been involved in a prang.

Annie Emmerson
BBC Sport triathlon expert & former GB triathlete

The front pack have really come together and worked as a team and that is showing in the time difference back to the second pack.

The USA are through to the final of the Men's 4x100m relay after a false start

Lap six of eight done and the 10-strong lead group - containing both Alistair and Jonny Brownlee - have cranked out another three seconds on the rest. Their advantage is up to one minute and 18 seconds.

GB's last Olympic badminton medallist... 

The crowds have turned out for this triathlon, packing in four or five deep as the lead group speed along Copacabana.

Catherine Harrison: Now that's what the Olympics are all about! Bronze from nowhere in the badminton. Fantastically done lads!

Max Turner: Get in there boys! What a match of badminton! Incredible sport and ranked 22ND!

Jon Blower: Beating China in badminton is like beating Mary Berry in a bake off. Amazing bronze medal for Team GB!

Who are the other eight riders then making up this select bunch at the front of the race?

Vincent Luis of France is the biggest threat to the Brownlee brothers, with Australia's Aaron Royle also a contender.

The others - South Africa's Henri Shoeman, United States' Ben Kanute, Slovakia's Richard Vargas, Andrea Salvisberg of Switzerland, Belgium's Marten van Riel, Italy's Alessandro Fabian - are unlikely to stand the pace when they climb off their steeds.

Their lead has popped up a couple of seconds to one minute and 15 seconds after the fifth of eight laps.

That's it! 

Marcus Ellis and Chris Langridge are Britain's first men's doubles medallists.

It was an attacking masterclass from the Brits.

21-18 19-21 21-10 the final score.

At halfway though the ride, the lead group - containing both Brownlees - has increased it's lead on the rest to one minute 13 seconds.

That is another 10 seconds on what they had after three laps of the cycle course.

Aimee Lewis
BBC Sport in Rio

There's a bigger crowd inside the Olympic Stadium now than there was an hour or so ago. The lower levels are fairly full, except for a section behind where the high jump is taking place, which is reserved for athletes. It's a healthier number, and a more vocal crowd, compared with the morning sessions at the 2013 World Championships in Moscow at least. 

Image source, .

The relatively small size of the lead pack - just 10 riders - is working in their favour.

Their chain-gang - each taking a turn on the front to push the pace forward before sitting behind and recovering - is working efficiently on the narrow twisting streets.

The lumpy main group is too unwieldy to get anything as efficient going. 

Richard Murray and Mario Mola's hopes are withering in the midst of it.

Ryan Kahr: The Brownlee brothers are making triathlon look easy!

David Talbot: Browwwnleeeeeeessss...!

Annie Emmerson
BBC Sport triathlon expert & former GB triathlete

We have seen Mola do amazing things from behind but against the Brownlee's it will be very, very tough indeed with the gap over a minute.  

The ten-strong lead group complete the third of eight bike laps.

The wait begins for the rest. And goes on. And on.

The gap is up to one minute and three seconds by the time the chasers cross.

It may be a straight slug-out for the medals between the Brownlees and France's Vincent Luis.

Tonia Couch is through to tonight's final after a fine last dive. She scored 71.40, taking her total score to 318.00 points and finish in tenth place overall. 

She will face a tough test against Chinese pair 15-year-old Ren Qian and 17-year-old Si Yajie, who both qualified with big scores. The final gets underway at 20:00 BST.