Jill Sinclair: Businesswoman and pop manager who co-founded ZTT and guided the career of her husband Trevor Horn

Sinclair and Trevor Horn: the success of ‘Relax’, their first hit, ‘was all down to her hard work,’ Horn said (Andrew Buurman)

The formidable Jill Sinclair described herself as a "woman who has made her own luck" and she deserved every award and accolade that came her way for her achievements in the male-dominated British music industry.

A former maths teacher, she had finely tuned ears and a wonderful business brain, and masterminded the rise of her husband Trevor Horn, the maverick musician turned record producer who soundscaped the 1980s with his state-of-the-art productions for Dollar, ABC, Yes, Grace Jones and Pet Shop Boys and went on to work with Simple Minds, Paul McCartney, Tom Jones, Rod Stewart and Robbie Williams.

In 1983, with the journalist Paul Morley, Horn and Sinclair co-founded the ZTT label and unleashed Frankie Goes To Hollywood, who scored three consecutive UK No 1s with "Relax", "Two Tribes" and "The Power Of Love" in 1984. Art Of Noise came next, Horn's collective whose groundbreaking use of samples shaped much of what followed, then the Teutonic noir of Propaganda. They went on to turn Seal into a global superstar in the 1990s.

Sinclair was comfortable doing a distribution deal on a handshake with Island supremo Chris Blackwell, who in 1983 gave her and Horn the keys to Basing Street Studios in Notting Hill, now Sarm West. The location for the recording of the Band Aid single "Do They Know It's Xmas?", whose 12in version was remixed by Horn, Sarm West became the main base for the SPZ Group comprising Sarm, ZTT, the Perfect Songs publishing company and the legendary Stiff label whose assets she and Horn bought for £300,000 following its collapse in 1987.

She could be a fearsome opponent. In the 1990s she stood up to Rob Dickins, then chairman of Warner Music UK, the next ZTT distributors, when he tried to absorb their label into the major. Her attempts to hold Frankie frontman Holly Johnson to the terms of his ZTT and Perfect Songs contracts when he signed a solo deal with MCA in 1987 resulted in a two-year legal battle and an eventual ruling in Johnson's favour. The singer relished recalling the whole saga in his 1994 autobiography A Bone In My Flute. The other members of Art of Noise and Propaganda also left ZTT though their differences were settled out of court.

Sinclair's life was curtailed by a freak accident in the grounds of Hook End Manor, the couple's Oxfordshire home, in June 2006. Unaware of her mother's proximity, her son Aaron was firing an airgun. A stray pellet hit Sinclair in the neck, severing an artery and causing irreversible brain damage. Cared for in a south London hospital, she couldn't speak, move or smile and could only show discomfort. Though she did not need a life-support machine, her condition had not changed when she died of cancer. When I interviewed Horn in January, the painful subject of his wife was mostly off-limits, but he couldn't help but be effusive in his praise for Sinclair, and explain the crucial role she had played in his career.

"It was all Jill's idea," he told me about the advice she gave him after they married in 1980, following his emergence with Buggles, whose hit "Video Killed The Radio Star" heralded the '80s, and his short-lived tenure with the progressive group Yes. "She took over managing me and said: 'You're not frontman material. I think you should concentrate on being a producer, that's your strength'. She was right.

"The first thing she wanted me to produce was Dollar. I didn't get it. I'd just played Madison Square Garden with Yes. She said, 'Do a Buggles record, they'll front it'. I wrote 'Hand Held In Black And White' and 'Mirror Mirror'. I was really taken by surprise that Paul Morley at the New Musical Express liked the result."

This led to the launch of ZTT, named after "Zang Tuum Tumb", a sound poem by the founder of the Futurist movement, Filippo Tommaso Marinetti. "Running a record label is not something to be taken lightly. I didn't anticipate how difficult it is even if we had a very successful first year. It took a long time for 'Relax' to be a hit. It was all down to Jill's hard work. She kept on and eventually Top Of The Pops gave Frankie a go and the next day the record went through the roof."

Born into a London Jewish family in 1952, Sinclair left teaching in 1977 and worked at her brother's studio, the original Sarm, in the East End. On her first day she met Horn, then a session bass-player, though both were dating other people and only became an item a few months later. After hearing a demo of "Video Killed The Radio Star" she convinced him of its potential and facilitated his transition from performer and songwriter to the most distinctive British record producer of his generation.

"He's one of the best in the world and to make recordings of that quality takes a tremendous focus," she told The Independent about Trevor in 1999. "I've always taken care of business and he's made great records. It's not very complex. I'm a bit of a donkey. I just work and I'm a great believer in grasping the opportunities that come your way. I'm a driven person. We're such an odd combination. I never had any doubts that Trevor would be an enormous success, but it was only when I was named Businesswoman of the Year that I thought about my own career at all. I had just worked and never had a plot."

The pragmatic half of the partnership, Sinclair admitted she had "never been much of a one for subtlety", but said that in time she became "much more patient and able to see things from the other points of view." A spell in California in the early '90s probably helped put things in perspective, especially after the couple nearly drowned swimming off Malibu.

ZTT also achieved major success with 808 State, while in 1996 Horn was presented with the Record of the Year Grammy for his production of Seal's "Kiss From A Rose". Sinclair was executive producer on the 2005 film adaptation of The Magic Roundabout, a complex project involving three different voice casts for the UK, French and US markets. Several tracks from Made In Basing Street, the 2012 album Horn recorded with fellow producers and musicians Lol Creme, Steve Lipson and Ash Soan under the name Producers, are inspired by Sinclair. The poignant refrain of "Garden Of Flowers" – "in a garden of flowers, that's where you'll be" – has become a feature of the occasional concerts he has given since.

PIERRE PERRONE

Jill Sinclair, pop manager and label founder: born London 5 April 1952; married 1980 Trevor Horn (three daughters, one son); died London 22 March 2014.