Development officer Janet Williamson first contacted the charity when her daughter Jodie, 38, who has a learning disability, was a toddler.
She was instrumental in opening the Buddys cafe, which is staffed by volunteers and people with learning disabilities, in 2007 and 18 months ago she opened the Mencap charity shop, also in South Farm Road.
Mrs Williamson, of East Preston, was nominated by her friend and neighbour Ann Smith, and will attend the national Pride of Britain Awards in London with her husband Mason, tonight (October 7).
The mother-of-two said: “I am really looking forward to the awards ceremony, it is very exciting.
“When Jodie was about two I decided that I wanted to find out more information about learning disabilities and to see what was available in this area. I wanted to raise funds to improve the lives of people and I love everything about working here. It is all about all the different people that you meet. This award is for all the volunteers. I am so pleased because it is putting us on the map.”