Construction work on the northern area of the square, officially known as Blocks K1, K2 and K3 and comprising odd numbers 19-33, began around 1959 with Fine Fare supermarket opening in October 1960. Block K3, numbered 29-33, was the last completed as part of the nearby Brooke House development. Grays Co-operative Society (Co-op) then moved into the last development of the first phase - Block J2 - around December 1961. This three storey building then became known as Co-operative House and numbered 106-114 Town Square.

No further development of Town Square took place until September 1970 when the corporation's next project named Block S commenced. The Block S development, known by name since 1963, was designed to fill in the remaining unused land on the north side and thus complete the town square look. Built at a cost of £1.5 million this development saw the completion of units 1-9 and the office complex Northgate House and High Pavement. Marks and Spencer were the first to open in the new units in November 1971. The entire square is pedestrianised.

During the late 1980s after many years of talk a scheme to roof over the square was announced complete with a model and exhibition. Despite local interest the scheme proved financially unviable and never materialised.

In 1996 a Town Square regeneration project to create an open plaza began and part of Keay House built over the square was demolished and the upper block was renamed Southgate House. Two large detached glass retail pavilions, named east and west, were also built around 1998 and in use soon after as a coffee shop (Costa Coffee) and hairdressers (Toni & Guy, 1999).