Thomson rode Boris when she won this contest in 1990 and the horse has been carefully prepared for his attempt at a repeat victory. He was given a quiet preliminary outing at Everdon 10 days ago, just after Thomson returned from Barcelona, where she finished ninth in the Olympic three-day event on King William.
For the past two years Pippa Nolan has been runner-up to Thomson at Gatcombe. On both occasions she rode Sir Barnaby, who is now 15 but as sprightly as ever as he prepares for another crack at the British Open. Nolan also rides Metronome, who was her winning partner at this year's Bramham three-day event.
Two former winners, Britain's Virginia Leng and New Zealand's Mark Todd, will be absentees. Both had entered but their horses were later withdrawn because they were not thought to be fully fit.
The main challenge to Thomson and Nolan may come from three of the New Zealanders who won team silver medals in Barcelona, Blyth Tait, Andrew Nicholson and Victoria Latta. Tait has talented mounts in Ricochet and Delta.Reuse content