Cardigan Castle dates back to the 12th Century

The Miners' Institute in Newbridge, south Wales, the old workhouse at Llanfyllin in Powys and Cardigan Castle are in the running.

Viewers voted during the hour-long programme on Tuesday which started at 2100 BST by calling 09011 332222.

The show aims to save an old building from ruin.

In all, 21 buildings across the UK have been chosen for the series, which is presented again by Griff Rhys Jones.

The Grade 2-listed Llanfyllin workhouse in Powys was built in 1838 and the estimated cost of its restoration is �3.5m.

It is a fantastic spread of history and the castle deserves all the support it can get Sue Lewis, Cardigan Castle

Wyn Morris, chairman of the workhouse's trustees, said the building was unique.

"There is nothing like it left in Wales," he said.

"It is something people can vote for and, in the future, it will provide something for the local community, local business and provide much-needed employment."

Cardigan Castle, which hosted the first National Eisteddfod, was bought by the county council last year, after falling into disrepair.

The estimated cost of its restoration, like Llanfyllin, would be �3.5m.

Sue Lewis, who is supporting its bid, said it was an interesting site because it has so many layers of history.

"You can go from the medieval castle through to the Georgian house - there is even a World War II pillbox there," she said.

"It is a fantastic spread of history and the castle deserves all the support it can get."

The youngest of the three Welsh nominations is Newbridge memo

The most recently built of the three nominations in Wales, the Workingman's institute and memorial hall in Newbridge was once the centre of the community.

Howard Stone, who is desperate to see it restored, said the hall had been "built with the blood, sweat and tears of men who worked in the mines".

"Enough of our heritage has been destroyed over the years".

"Our future generation should have the benefit of enjoying the heritage we have enjoyed."

It is estimated that �2.94m would be needed for its restoration .

Online viewers will be able to access virtual tours of all the buildings in the running for the live final.

A minimum of 34p from every phone vote will go to the Restoration Fund and the winning building will be restored from funds raised.

Last year, the Victoria Baths in Manchester won �3.5m after winning the UK final.