Cambridge’s tallest building, a Catholic church, has been restored, bringing back into view the craftsmanship of 19th-century stonemasons.

The Church of Our Lady and the English Martyrs (OLEM) has been covered in scaffolding since restoration work began in February.

The Diocese of East Anglia embarked on an emergency restoration programme at the Grade-1 listed church after the discovery of serious issues with the high-level stonework and pinnacles of the church tower.

Selective stone cleaning has since removed over a century’s worth of pollution and grime, which has been described as “mind-blowing” by one stonemason.

Ryan Logan, a stonemason who has contributed to repairs, described modern stonework as involving “a lot of power tools, a lot of machinery,” whereas the masonry of OLEM “was created with just manpower, a mallet and chisel”.

The church was designed in the 19th-century gothic revival style and was erected in the span of five years, consecrated in October 1890. Mr Logan added that “it’s nice to be working on it and restoring it back to how it should be”.

The church was originally a honey colour when it was constructed. However, years of pollution left deposits of dirt on the rock, turning it black by the middle of the 20th Century.

Removing the pollutants has, however, exposed a number of other problems – from eroding stonework, to cracks and fissures.

While an initial £100,000 has already been raised, the extent of the issues has forced OLEM to increase their fundraising target.

The renovation to the south aisle roof, masonry repairs to the bell tower, and wrap-around scaffolding for the whole tower has so far cost £1,000,000.

Meanwhile, the money already raised has contributed to the completion of a new boiler system, as well as repairs to finials and the rectory parapet.

As the largest Catholic Church in Cambridge, OLEM has had a long association with the University of Cambridge and its colleges.

The church contains a 16th-century statue of the Virgin Mary which originally belonged to Emmanuel College, while its stained glass windows contain depictions to the University’s colleges.