Public relations executive, teacher and special adviser to Gordon Brown on his culture strategy in the runup to the 2010 election
As director of the communications consultancy Brunswick Arts, Helen Scott Lidgett, who has died aged 63 of ovarian cancer, was involved in such projects as launching the Baltic contemporary art centre in Gateshead, the British Galleries at the Victoria and Albert Museum in London, numerous British Council pavilions at the Venice Biennale and the French government's Paris Calling initiative. For work on promoting French art in Britain under this scheme, in 2008 she was made a Chevalier de L'Ordre des Arts et des Lettres, and pinned the medal up on her bedroom wall, alongside her Brunswick card and pictures of her children.
Helen was born in Golders Green, north London, to Bernard Finch, a doctor, and Patricia, a sculptor. Her parents, unconventional, non-practising Jews, sent her to the progressive King Alfred's school, but finding it too un-academic for the already studious Helen, soon moved her to Henrietta Barnett school.
At St Martin's School of Art, she met her first husband, Duncan Scott Lidgett. They became stallholders in Camden Market, selling secondhand clothes and dresses designed and made by Helen using antique fabrics and lace she had collected – all her life she was an epic collector of fine things throughout her life). Focusing on the lace, They went on to open a successful wedding dress shop, Scott's, supplying Liberty and Selfridges.
Endlessly energetic, in 1974 Helen was appointed head of art at Camden school for girls. The music-video director Sophie Muller and I were pupils there, and became lifelong friends of hers. In 1982, Helen and Scott divorced, but she continued to run the shop on her own, while working as a critic and arts writer for the London listings magazine Time Out, running an art gallery, The Boat House, on a vessel in Camden Lock, and bringing up two children.
Eventually Helen sold Scott's, and in 1990 went to the art publishers Thames & Hudson as head of publicity. At the firm's 50th anniversary party in 1999, Helen met a new face on the arts PR scene, Sarah Macaulay. The pair formed an enduring friendship, and Helen eventually joined Sarah's firm, Hobsbawm Macaulay. In 2001 Sarah, by then married to Gordon Brown, the Labour chancellor, retired from the business. But before doing so she and Helen set up an arts subsidiary at Brunswick. Alan Parker, its chief executive, recalled how "the power of Helen's infectious enthusiasm combined with her special talent to see how things could fit together, the potential in everything".
In the runup to the 2010 general election, Helen took a sabbatical from Brunswick to advise Brown on his culture strategy. As an adamant supporter of the importance of arts education in schools and of free entry to museums and galleries, she was a natural fit. Obviously her "special adviser to the PM" card went up on the wall, too.
Helen was irreverent while always well informed, relaxed yet authoritative, exacting yet never judgmental. She believed passionately that anyone could succeed if they got the right encouragement, and she made it her life's work to ensure that all those with whom she came into contact did. Generous-spirited and a fantastic laugh, Helen was my mentor, my confidante, the person with whom I felt most at ease – who else would have danced on Scott's shop counter with me to Get Down on It by Kool and the Gang?
She is survived by her second husband, Johnny White, whom she married in 2002, and their son; and by the daughter and son from her first marriage.
• Helen Scott Lidgett, public relations executive, born 26 November 1948; died 31 July 2012