Equestrian star Ian Stark, one of Britain's main hopes for a medal in the Olympics this year, has withdrawn from the Bramham Horse Trials, which were starting this afternoon.

He was scheduled to ride Rangitoto at the event near Wetherby but is keen to take no risks ahead of Sydney, which is only 100 days away.

His absence sees New Zealander Blyth Tait as the hot favourite at Bramham on either of his two mounts, Chesterfield and Aspyring.

Kristina Gifford is expected to mount a challenge with her horse, Marly.

The inspection of horses was taking place today. Tomorrow and Friday sees the senior riders take their dressage tests ahead of the cross country phase on Saturday. The competition for senior riders ends on Sunday with showjumping.