in those early days of the public service all the live prestel computers were located in st alphage house, a 1960s office block on fore street in the city of london. at the time the national operations centre (noc) was located in the same building on the same floor. the computers and the noc were later moved to baynard house, (on queen victoria street, also in the city of london) which acted as a combined udc and irc. both types of machine, together with other development hardware, remained in service there until 1994 when the prestel service was sold by bt to a private company.