The General Post Office (G.P.O) of the United Kingdom carried the sole responsibility for providing telecommunication services across the country with the exception of Hull. The GPO issued a range of telephone instruments to telephone service subscribers that were matched in function and performance to its telephone exchanges. Until October 1969, the GPO had a monopoly on the provision of all telephone lines and telephones within the UK, other than in Kingston upon Hull, which for historical reasons was unique in maintaining its own municipal telephone service. From the 1st of October 1969, the Post Office Corporation replaced the General Post Office with ownership of the former GPO business. Customers of the PO (known internally as “subs”, short for ‘subscribers’) did not own their telephones. They were instead rented from the G.P.O. The 700 series was a modern telephone handset model with a tangle-free spiral handset cord. The 706 telephone was first released in 1959. The 711L model was essentially a 706 base with a modified frame and case. First introduced in 1961, it could also have either a steel or plastic base and hardwired or printed circuit internals, depending on the manufacturer. It was installed when the subscriber wanted a wall-mounted device. In the late 1960s you introduce the Trimphone. The original design by Martyn Rowlands, (industrial designer) dates back to 1964. In 1965 the first experimentally, but was not available to everyone until 1968. The original Trimphone was the 712, however it took several revisions to get it right and a much-improved model, the 722, was released in 1966 and released as 1/722 with a revised version, the 1/722 MOD, quickly following. A further improved version, the 2/722, became the base model in late 1971. The model 741 was the corresponding wall telephone that came to replace the type 711. In 1967 you introduced the type 746 which was very similar to the model 706.