'This proposal will excite walled towns and their peoples across the length and breadth of Europe,' said leader John Price.
It is intended that the wall will form a millennium quarter in the city, a focus for arts and leisure in the north-west. Its Roman walls are about 2,000 years old, while the medieval ones are 1,000.
A council spokeswoman said local people liked the idea but did not understand why the council was planning to spend thousands of pounds on a wall instead of on council services. Members are writing to local papers to explain how the millennium fund works.