Olympic champion Alistair Brownlee will look to complete his set of titles in Thursday's Commonwealth Games men's triathlon in Glasgow.
In addition to his success at London 2012, Brownlee is a two-time world champion and recently won the European title for fourth time in Kitzbuhel.
Brownlee will be joined by brother Jonny, a world former champion and Olympic bronze medallist, with South Africa's Richard Murray, New Zealand's Ryan Sissons and Australia's Aaron Royle expected to be their main rivals.
Meanwhile, in the absence of Welsh world champion Non Stanford, England's world number two Jodie Stimpson is the top home hope in the women's race.
Sir Bradley Wiggins returns to the velodrome in England's team pursuit quartet - the event in which he hopes to bring the curtain down on his Olympic career in Rio.
Wiggins has won it all in cycling - from the Tour de France to four Olympic golds - but has never stopped on the top step of the podium at the Commonwealth Games - winning the last of his three silvers 12 years ago in Manchester. He'll be joined by Ed Clancy, Steven Burke and Andy Tennant in a powerful looking team.
Elsewhere, Olympic champions Jason Kenny and Philip Hindes will be joined by Matthew Crampton in England's team sprint squad, where Australia are expected to be the key rivals.
Olympic silver medallist Michael Jamieson is the big Scottish hope as he seeks to upgrade his London 2012 medal in the 200m breaststroke while two-time Olympian and former world medallist Hannah Miley will be among the favourites in the 400m medley.
"I've woken up for training every morning with the world-record time on my alarm clock," said Jamieson, who is seeking to better Akihiro Yamaguchi mark of 2:07.01
"It's the first thing I see when I wake up. Psychologically, that's what I'm aiming for."
In the rhythmic gymnastics, Mimi-Isabella Cesar, Lynne Hutchison and Stephanie Sherlock will compete in the team event - in which England claimed bronze four years ago - and will also seek to qualify for the individual events.
In weightlifting Jo Calvino will look to win a Commonwealth Games medal at her fourth attempt, having placed sixth, fifth and fourth previously.
And two members of the London 2012 Olympic team are among those challenging for judo medals, Ashley McKenzie and Colin Oates.
Elsewhere, there are preliminary events in badminton, squash, table tennis and lawn bowls.
And competition starts in hockey as England's women look to rebound from a disappointing World Cup campaign against Wales, while England's men's team take on Trinidad and Tobago.
Medals decided today
Swimming: men’s para-sport 100m freestyle S9, 400m freestyle, 200m breaststroke; women’s 200m freestyle, 400m individual medley, 4x100m freestyle relay.
Cycling (track): men’s 4,000m team pursuit, team sprint; women’s para-sport sprint B tandem, 500m time trial.
Gymnastics (rhythmic): women’s team.
Judo: men’s -60kg, -66kg gold and bronze medal matches; women’s -48kg, -52kg, -57kg.
Triathlon: men’s and women’s individual.
Weightlifting: men’s 56kg, women’s 48kg.
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