Smith, who has played with anyone who is anyone in the world of music, including The Waterboys, Roxy Music and Patricia Kass, was found at his Battersea home last night.
He had been due to play a show at the 606 Club, but when he failed to show his bandmates, including Jeremy Stacey, went to his house and discovered him.
Producer Robin Millar, who met Smith in 1990, and worked with the bassist and keyboard player on several Kass recordings says he was one of the "true unsung heroes". Millar adds, "Mark was one of the great people and players. He was one of those guys who never pushed himself forward, but was a great all round musician - a real musicians' musician."
Millar expects that his colleagues will organise a memorial for Smith shortly.