Louisa Brassey, 22, stormed to the top of the leaderboard after dressage at the Blenheim International Horse Trials on a score of 41.7.

Riding her own 13-year-old Bruce Rock, Louisa looks well on track to improve on her 14th place here last year.

Louisa is based not far from Blenheim, at Tetbury in Gloucestershire — in the heart of the Duke of Beaufort’s hunting country. Her father Anthony is chairman of the Beaufort and Louisa, whose ambition is to jump round the Foxhunters at Aintree, has managed two days autumn hunting already this season.

Bruce Rock missed three months of the season after sustaining a torn muscle at Chatsworth, but Louisa says that she is looking forward to the cross-country: “He’s so genuine and I trust him implicitly.”

A mark behind on her on 42.8 is the eight-year-old Happy Times, ridden by Australia’s Sam Griffiths. Sam is trained by Jennie Loriston-Clarke, who was here warming him up today.

“I didn’t dare do anything wrong,” he joked.

Sam, who was 11th at Burghley last week on Connigar Bay, was fourth at the Le Lion d’Angers young horse championships last year on Happy Times.

“I think the world of him,” he said. “This is his first three star and it will be a big ask — the two narrow fences on a curving line out of the water are really tough — but I’m hoping for a really good run.”

Kristina Cook rode the exciting nine-year-old Thoroughbred Miners Frolic into third place with a mark of 43.9, and half a mark behind her on 44.4 is last year’s Le Lion seven-year-old winner, Lord De Ligniere, partnered by Frenchman Aurelien Kahn.

Barbury heroes Chris King and The Secret Weapon are lying fifth on 45, ahead of Thursday dressage leaders Polly Stockton and Regulus.

Blenheim CCI*** results after dressage

1st Louisa Brassey (Bruce Rock) 41.7
2nd Sam Griffiths (Happy Times) 42.8
3rd Kristina Cook (Miners Frolic) 43.9
4th Aurelien Kahn (Lord De Ligniere) 44.4
5th Chris King (The Secret Weapon) 45
6th Polly Stockton (Regulus) 47.2
7th Clayton Fredericks (Dunges Laurent Rose) 48.5
=8th Edward Stibbe (Dusky Moon) 48.7
=8th Caroline Powell (Mac Macdonald) 48.7
10th Jo Aston (Southern Rumour) 50