Briony Frost rides Pacha Du Polder to victory in Foxhunter Chase

Frost rode to a thrilling narrow victory over Katie Walsh

Briony Frost completed a historic familial treble with her winning ride (Getty)

Pacha Du Polder, an 18/1 outsider, has won the catchily-named St. James's Place Foxhunter Challenge Cup Open Hunters' Chase, giving trainer Paul Nicholls his first win of the festival.

Briony Frost rode to a thrilling narrow victory over Katie Walsh on Wonderful Charm as Nicholls enjoyed a one-two in the race.

It completed a historic treble for the Frost family, with father Jimmy winning the National in 1989 and brother Hadden winning the Pertemps in 2010.

The pre-race talk and betting had focused on On The Fringe winning a third successive Foxhunters, however Jamie Codd was unable to do it, the horse never really threatening the leaders and having to settle for fourth place.

Balnaslow had led the way for much of the race, still leading with two fences to jump, but Pacha Du Polder was well placed just behind and just had enough in the tank to hold off a very spirited late charge from Wonderful Charm and Katie Walsh.

Barel of Laughs finished in third, a great result for a horse that started the race as a 100/1 no hoper.