OXFORD University wants to undertake a ‘highly intrusive overhaul’ on the listed building which includes the libraries of its English and law faculties.

The St Cross Building designed by Brutalist architect Sir Leslie Martin is described as a leading example of post-war architecture.

But a leaking roof and degrading skylights in the Grade II* listed building mean they now need to be replaced.

Read again: Part of city centre could be divided into three to help conserve it

A document written on behalf of the university’s estate service states: "The existing roof finishes and skylights have reached the end of their design life and have degraded to the point where significant levels of moisture (and in some cases severe leaks) are entering the internal environment.

Oxford Mail:

"This has in turn caused the compressed straw slabs which form the structural roof deck to start losing structural integrity."

"It is clear that some form of significant overhaul or replacement is needed.”

The original idea of the building was formulated from 1958 by Sir Leslie, who is most famed for his design of the Royal Festival Hall in London.

Read again: Latest planning applications to Oxford City Council

He was assisted by Patrick Hodgkinson, who completed design work on the Brunswick Centre in North London initially started by Sir Leslie, and Sir Colin St John Wilson.

In the late 1950s, it had been hoped to provide separate buildings for Oxford University’s English, law and statistics departments, but work found the Manor Road site was too small for three buildings and so the single unit was chosen.

Sir Leslie designed the St Cross Building around the concept of a ‘group of buildings clustered around a raised courtyard’.

Oxford Mail:

Despite its architectural merit, changes have been made since it was opened in 1964. Two new lift shafts and a new staircase were built during major work undertaken in 2016 to improve access.

Copper roofing was replaced in the 2010s and the former statistics library skylights were reconfigured in 2012. A car park was built along the building’s northern boundary and lawn area during the 1980s.

The building was given Grade II* listing in March 1993.

It is located opposite St Cross Church, which dates from the ninth century, is Grade I listed and is now used as a historic collections centre by the university.

Read again: Latest on £200m plan to redevelop Oxpens

Holywell Manor, also nearby, dates from the 15th century, is Grade II listed and is owned by Balliol College. It houses some of its postgraduates there.

The university has submitted its plans for the St Cross Building to Oxford City Council, and members of public can see them online at oxford.gov.uk or at the town hall in St Aldate's.

The application is expected to be decided in the coming months, either by a council planning committee or a designated officer.