old codes in January 1970 and from April the parallel operation was withdrawn in the other five cities. The change to all-figure dialling was controversial and was debated in both Houses of Parliament. Among the criticisms of the new system was the perceived difficulty in remembering telephone numbers, the inability to easily recognise where a telephone number was located and the need for a change so soon after the implementation of subscriber trunk dialling. See also All-number calling, the United States equivalent. References External links Different standards for letter-number correspondence on phone keypads Telephone numbers in the United Kingdom