ONCE it housed the Durham miners' parliament but it has not been filled with the sound of debate for 12 years.

But a rare chance to go into the chapel-like debating chamber at the Durham NUM headquarters in Redhills Lane, Durham City, is coming up later this month.

Heritage Open Days have become the country's biggest and most popular free cultural event in which thousands of interesting places normally closed to the public welcome visitors.

This year's event, from Friday to Monday, September 13 to 16, will see the impressive Redhills Miners' Hall opened up by the NUM.

The building, with its neo-Georgian facade and distinctive cupola, is a familiar sight to passengers on trains pulling into Durham station on the nearby East Coast Main Line.

The Durham Miners' Association, formed in 1869, built the hall between 1913 and 1915 for £30,000.

In the heyday of the Durham Coalfield it had a staff of about 40 and the chamber was where union delegates from each pit - at one time there were 200 employing 200,000 men - discussed the welfare of their members.

"The chamber was designed along the lines of a Methodist church because our early leaders were primitive Methodists, Ranters,'' said George Robson, former NUM finance officer and organiser of the Durham Miners' Gala.

David Guy, NUM area president, said: "They debated every aspect of mining working conditions, wages, social activities and politics.

"The mining communities were the forerunner of the welfare state.

"We had our own nurses, paid for by the miners, our own welfare, sporting facilities and we provided housing for the elderly and convalescence homes.

"Clem Attlee, I'm absolutely sure, would have been influenced by what was taking place with the miners in the founding of the welfare state.

"In those days the miners had a big influence on the Labour government. We were the largest coalfield.''

The last time the chamber was used was for the NUM annual conference in 1990, an occasion Mr Guy describes as "very atmospheric''.

Since the death of the coalfield in 1994, the union has struggled to retain the Grade I listed building.

The chamber, with its old banners and paintings of ex-leaders, is in mothballs because of the high cost of rates.

But Mr Guy hopes to form a Friends of Redhills, a charity that would use the chamber for concerts _ "it's got great acoustics'' _ and educational and heritage events.

He also believes it would make an ideal seat for the proposed North-East Regional Assembly.

Sadly, most of the visitors to Redhills these days are ex-miners who are seeking compensation for diseases brought about by their former occupation.

With interest in the county's mining past growing, the NUM hopes there will be plenty of people interested in visiting the hall and its grounds, which includes a memorial to the victims of the Easington pit disaster of 1951.

Tracey Ingle, of Durham City Council, said: "People have seen Redhills from the outside, from the railway but they have never been inside it. I'm sure there will be a lot of former miners and their families who will be interested.''

Heritage Open days are organised by English Heritage and the Civic Trust.

Tours of Redhills Miners' Hall take place next Friday at 3.30pm, on Saturday, September 14, at 11.30am and Monday, September 16, at 3pm and 3.30pm. They should be booked through Durham Tourist Information Centre on 0191-384 3720.

* For your full guide to the North-East's hidden attractions see next week's Seven Days.

Also every day next week The Northern Echo will be publishing a selection of the best undiscovered gems for you to visit.