THE most successful British racehorse trainer of all time has won support for his plan to build an all-weather riding school so large it would also serve as a wind break, despite it being on land overlooked by the Yorkshire Dales National Park.

Mark Johnston, who broke the record with 4,194 wins when Frankie Dettori rode Poet’s Society at York in 2018, has applied to Richmondshire District Council to create the 60m by 40m facility at his stables in Middleham.

The scale of the proposed building – more than nine times the area of a tennis court – means the scheme is regarded as “major development” and consequently will be scrutinised by the authority’s planning committee next week.

The 300-acre yard Mr Johnston runs with his wife, Deirdre, and son, Charlie, already boasts some of the finest facilities in Britain for the care and training of racehorses, including three grass gallops, an all-weather Tapeta gallop, an equine swimming pool, covered automatic exercisers and starting stalls to practise breaking quickly.

Application papers lodged by an agent for Mr Johnston, whose victories have earned £53m in prize money, state his Kingsley Park Farm complex only has external riding facilities, “which causes issues during ice and snow and extreme weather conditions”. The documents state while the racing yard is “well established and progressing year by year”, the building would add “a much-needed wind break to the existing hard standing”.

The application adds: “The building purely adds another facility to the yard allowing for a more economical system when the weather does not allow some horses to be exercised outdoors.”

The papers state the planned orientation of the building, tree planting and a move to dig it three metres into the land would reduce the landscape impact across the valley and from the national park.

Middleham Town Council has backed the scheme, but called for action “to minimise additional light pollution and visual impact which, during the winter in particular, is already quite significant”.

In a report to the planning committee, planning officers said as the proposed building would only be seen from the other side of the valley to the north near Leyburn, the planned landscape mitigation measures would mean there would not be a significant harmful landscape impact.

The report adds the authority’s strategy for Lower Wensleydale gives specific support at Middleham to developments and infrastructure related to the horse racing industry.

Recommending the plan be granted, planning officers concluded: “The proposed development will provide enhanced facilities at, and support, an existing established farm and business with an essential requirement to have a countryside location. The building will be sited and designed to minimise landscape impact and will not significantly harm the character of the countryside.”