THEY spent three years lovingly polishing all the huge windows and delicately cleaning every inch of stonework.

Even the golden cockerel, which sits 62m above Oxford’s High Street, was given a new lease of life during the refurbishment of the city’s most famous spire.

Yesterday, the Duke of Gloucester visited the University Church of St Mary the Virgin to cast his eye over the £5.1m restoration and was welcomed by the Rev Canon Brian Mountford, the church’s vicar.

Mr Mountford said: “The building has been transformed by this restoration.

“It was a bit of a nightmare when the inside of the building was full of scaffolding for six months so I am pleased the work is over.”

As part of the work virtually all the stonework of the Grade I-listed building was cleaned and restored using lime mortar to make sure the colour was left unchanged.

The clock was taken down and cleaned, while the bells, some dating back more than 400 years, were restored to their former glory.

Yesterday they rang out in celebration. Among the grandees attending the opening ceremony was the Chancellor of Oxford University Lord Patten. He said: “It is terrific. This is the first time I have been here since the refurbishment and it has been wonderfully done. This church is an important part of this city’s history.”

Inside the church the woodwork was also cleaned and waxed, revealing leaf patterns in the stalls, which no-one knew were there, and the walls and ceiling were repainted.

A celure – a representation of the heavenly sky – has been added to part of the roof .

Each of the monuments inside the church had to be treated using different techniques as they dated from differing periods and were constructed using different materials.

Architect Oliver Caroe, who ran the operation, said: “This church is right in the heart of a huge field of English history.” The project has been paid for with the help of the Heritage Lottery Fund, which gave £3.4m towards the restoration. It is hoped the church, which welcomes 300,000 visitors a year, will also be able to host concerts, exhibitions and other events.

The Duke of Gloucester said: “It always seems to me that one of the great things about this country is that in so many places you find the central feature is the parish church.

“And it is no surprise to find that Oxford is no different, except that this being Oxford the parish church is rather grander and more historic than average.”

He also visited Vale House in Sandford-on-Thames, to open the dementia care home’s new building, and Abingdon, where he marked the £3m restoration of the County Hall Museum.