The 1970s


St. Mary's is well placed for transport and the catchment area was enlarged during the seventies. The school became five-form entry with an age range of 11 to 18 years, and the first all-ability intake started in 1973. This required further buildings and a contract was signed in January 1972 for a further 674 sq. m. two-storey block (Sherwin) which was completed for the increased comprehensive intake. This cost £60,000 of which the LEA contributed £6,000. 

In 1974, several parts of school had to be evacuated until declared safe. This was due to the High Aluminia cement (HAC) crisis. HAC concrete was effectively banned for use in new structural concrete in the UK following a few well publicised collapses in the 1970s. Time and experience have shown that the primary causes of these collapses were poor construction details or chemical attack, rather than problems with the concrete itself.

St. Mary's Under 15s team won its first football trophy during the 1974–5 season.

Further plans were made to accommodate the annual build·up of pupils. An increase in specialist teaching rooms was required, and as the original building had only one or two for each subject it was impossible to create integrated departments without remodelling many older rooms for a changed use. This created problems for the builders and the school, as teaching had to continue throughout the construction. In October 1973, work on a new contract costing £442,000 began and continued until October 1975. The LEA's contribution was £132,000. It included the Sports Hall, extensions to the library, staff, and administrative rooms, added a further 1,905 sq. m. and accommodated more than 350 extra pupils. 

The 1962 site was now too small and more land was acquired. The playing fields covered 16 acres (65,000 m2) in addition to land occupied by buildings and paved areas. Construction on the sixth form centre, the Clitherow Building (named after  Saint Margaret Clitherow) started in May 1978 and provided another 676 sq. m. at a cost of £117,000. It provided classrooms, seminar rooms, a Sixth Form Common Room and two laboratories. The school was fully comprehensive from September 1979, with a five/six form entry, varying from 150 to 180 per year and 950 pupils on roll. There were 50 members of staff. 14 subjects were offered to the Sixth Form. The Clitherow Building was blessed by the Bishop of Leeds, the Right Reverend William Gordon Wheeler in November 1979.