Armstrong, who took on the position on an interim basis in 2015 prior to last year's Paralympic Games in Rio de Janeiro, will start with immediate effect.

She will combine the role along with her current position as head of performance for the world-class programme.

Armstrong will be tasked with maintaining the incredible record of the British Para-dressage side, who remain unbeaten at the Paralympic Games and European and World Championships since its introduction in 1996.

She will oversee the build-up to the Tokyo 2020 Paralympic Games.

"I'm absolutely thrilled and delighted to be back working with the team through to Tokyo," she said. 

"We are fortunate in the UK to have an excellent structure in place, with British Dressage working in conjunction with the Riding for the Disabled Association, which ensures the continued development and progression of the sport. 

"The Tokyo cycle will present a massive challenge to the squad; not least the proposed changes to the squad team size but also the environmental challenges at both the 2018 World Championships and the Paralympic Games. 

"With the support of a fantastic group of team practitioners and a talented group of athletes, I am confident that we will deliver our best performances at both next year’s qualifying event and, when the time comes, in Tokyo."

BEF chief executive Clare Salmon said she was "delighted" Armstrong had agreed to take on the role on a full-time basis.

"She has been a key voice in helping us to shape the future direction of the world-class programme in her position as acting performance director, and I know she will relish the challenge of identifying the marginal gains that will keep us at the top of the sport," she said. 

"The environment she has created within the Para-dressage podium squad to date has been superb and her experience within the sport and the world-class programme will help to ensure we are best prepared for Tokyo.

"Following the Rio review, we recognised that we needed to enhance our operational support structure within the world class team, and we will shortly be looking to begin recruitment for an operational manager to support Sarah in this area in the build-up to next year’s World Championships and the 2020 Olympic and Paralympic Games."