AN Indian summer helped swell the crowds as some of the region's best-loved historic attractions opened their doors this weekend.

English Heritage said it was confident that more than 800,000 people had enjoyed a free day out as part of Heritage Open Days.

Nationwide, more than 2,500 properties, including hundreds in North Yorkshire and the North-East, were open free of charge as part of the event, sponsored by civic trusts with the support of English Heritage.

David Fraser, English Heritage's regional director, said: "The open days offer a wonderful opportunity to enjoy our rich history."

Highlights in North Yorkshire included a tour of the Victorian mortuary at the Ripon workhouse, and the chance to retrace some of the long defunct railway tracks south of Pickering with the writer of a biography of George Stephenson.

In the North-East, Durham Castle opened its doors as did Darlington's clock tower, recently featured on the BBC Restoration Secrets programme.

But the Durham Castle event was so over-subscribed that it became a victim of its own success.

The castle is home to University College, where students and staff live and work. The gates only open to the public on guided tours, to make sure the academics are not disturbed.

But the guides could only take a total of 40 people at a time on the 30-minute tours and some people left disappointed.

Darlington Arts Centre allowed visitors a view of the majestic building when it opened its doors yesterday.

Among the entertainment on offer between 11am and 5pm was live music and children's treasure hunts, as well as the chance to take part in sessions and workshops.

Visitors got the chance to take a behind-the-scenes look at the centre, which has had more than 60,000 people from more than 900 groups attending events in the past year, as well as putting on 450 workshops and courses for children and young people.