Francis Monkman, multi

He was also a classical harpsichordist as well as writing for films, including The Long Good Friday

Francis Monkman, who has died of cancer aged 73, was a musician who co-founded Curved Air, one of the biggest names in progressive rock in the early 1970s; one of the few artists to enjoy top-level careers in both classical music and rock, he went on to join Sky, the band formed by the guitarist John Williams, which fused the two genres to great acclaim.

Anthony Francis Keigwin Monkman was born on June 9 1949 in Hampstead, north London. His father Kenneth was a journalist, and an authority on Laurence Sterne; he restored Sterne's house, Shandy Hall, where Tristram Shandy is set; Francis's mother was Vita, née Duncombe-Mann.

It was a musically privileged upbringing, and his music-loving parents had a harpsichord made for him. He attended Westminster School, where he studied the organ and harpsichord, and went on to the Royal Academy of Music.

Walking through a music shop he met Darryl Way, a student at the Royal College of Music, who was trying out an electric violin. They eventually formed a band they named Sisyphus, which evolved into Curved Air. The name was suggested by Monkman, a fan of Terry Riley's piece A Rainbow in Curved Air, and they were joined by the pianist Nick Simons, bassist Rob Martin, drummer Florian Pilkington-Miksa, and the singer Sonja Kristina, fresh from the London production of Hair.

Their rise was rapid, and in 1970 they became the first British band to sign for Warner Bros. Championed by John Peel on the radio, they released their debut album, Air Conditioning, that November, which reached the Top 10 (it was also notable for being the first commercially available picture disc LP). As Rob Martin had a hand injury, Monkman played all the bass parts, besides electric guitar and an impressive array of keyboards.

The peak of Curved Air's career was their second single Back Street Luv, which reached No 4 in the UK, thanks in part to the band's only appearance on Top of the Pops. It was the lead track on Second Album, which reached No 11 but was less well-received than its predecessor.

The third album, Phantasmagoria (1972) reached the Top 20, but by then the band was tired and broke. "We were all dead beat," Monkman recalled. "We’d just been told that if we toured the US three more times before next spring, we might just about break even."

The group fell apart, and Monkman worked with fellow prog-rockers Renaissance and with Robert Wyatt, as well as doing session work. But in 1974, with a large VAT bill to pay, Curved Air reformed for a three-week tour, which, alongside the resulting live album, refilled the coffers, after which Monkman departed again. (The drummer Florian Pilkington-Miksa also quit for a second time and was replaced by Stewart Copeland, who would go on to marry Sonja Kristina and find lasting fame with the Police.)

Besides his session work, Monkman gave harpsichord recitals. One at the Purcell Room on the South Bank in London in 1976, demonstrated, according to the Telegraph, "a forthright performing style with a palpably physical response to keyboard gesture allied to a splendid technique … The programme ended with a sequence of Scarlatti sonatas, music for which Mr Monkman's combination of structural control and brilliant keyboard flair was ideally suited."

He played alongside Brian Eno in 801, the band formed by Roxy Music's Phil Manzanera, and in 1979 he joined Sky, founded by John Williams, with colleagues including the bassist Herbie Flowers (probably best known for the bass line on Lou Reed's Walk on the Wild Side).

Monkman's harpsichord featured heavily on the band's version of Bach's Toccata, which reached No 5 in the UK and saw him make his second appearance on Top of the Pops. The band's busiest composer and arranger, he also began taking on soundtrack work, and the success of his music for John Mackenzie's classic gangster film The Long Good Friday (1980), with its thrilling theme tune, led to him quitting Sky to concentrate on his solo work.

Other film scores he played on included The Empire Strikes Back, Raiders of the Lost Ark, Superman II and the James Bond films The Spy Who Loved Me and Live and Let Die, as well as episodes of The Sweeney, Panorama and Prisoner: Cell Block H.

In 2008 he initially agreed to sign up to a Curved Air reunion but then backed out. "He wasn't willing to compromise," said Darryl Way.

Francis Monkman married Uiko Chida; they had a daughter but divorced. His daughter predeceased him.

Francis Monkman, born June 9 1949, died May 11 2023