SECRETS of some of Oxford's most beautiful and historic buildings were shared with the public this weekend.

Open Doors returned on Saturday and yesterday for its 12th year, offering free access to sights that are usually kept behind closed doors.

About 150 venues took part, from colleges to council buildings, including some that were new to this year's bill.

Oxford Preservation Trust runs Open Doors every September, in partnership with Oxford University, in celebration of the city.

Debbie Dance, the trust's director, said: "Open Doors has been running for 12 years, and we are still revealing more of Oxford's treasures.

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"We are so lucky to live in such an extraordinary place and want everybody to share that and enjoy it.

"If they care about Oxford, that helps our work. Lots of people join in to support us, and know us for this event - many people come to see us [in Cornmarket] and tell us how much they enjoy it."

A unit inside Oxford's Covered Market was welcoming visitors this year, in a space occupied by John Lindsey & Son Butchers' until they moved out last year.

Oxford Preservation Trust is working with Oxford City Council to transform the historic workspace, which was built in about 1849, into three new units.

The team has stripped out the interior and discovered original flooring and ironwork, and displayed information for visitors about the history of the shop.

Also open to the public once again this year was one of the event's most popular attractions - the Painted Room in Cornmarket.

A narrow staircase leads to the room, above the Vodafone shop, where visitors can find a 14th century tavern with striking Elizabethan wall paintings.

Open Doors fans have been known to queue outside to access the room, and are particularly fascinated by its link to William Shakespeare, who apparently stayed there during trips between London and Stratford-upon-Avon.

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Thames Valley Police and Oxfordshire Fire and Rescue Service both had a proud presence at the festival this year, with police offering children the chance to sit in the police van outside Oxford Castle.

Lincoln College Library, housed in All Saints Church in Turl Street, was also open to visitors.

Home to 33,000 books in the main shelves plus 10,000 in the historic collection, the impressive building is usually only open to Lincoln College students and staff.

Almost 1,000 visitors had already been inside when the Oxford Mail visited on Saturday afternoon, with more expected on Sunday.

Lincoln College librarian Lucy Matheson said: "People say they have been past the building so many times, and it's quite hard to make sense of from the outside.

"It has quite a draw - people wonder what's in here."

Last year the library received 4,000 visitors over the two days.

Open Doors also provided the chance for people to tread along the Iffley Road running track, where Sir Roger Bannister famously ran the first sub-four-minute mile.