Dumbarton Castle is opening its doors to visitors free of charge at the end of the month in a national campaign highlighting some of the country's most iconic attractions.

A ticket giveaway by Historic Environment Scotland’s (HES) will give free access to the castle which sits high on Dumbarton Rock.

The castle, which has a history going back 1,500 years, guards the point where the River Leven joins the River Clyde.

It was an important royal castle in the Middle Ages and, in later centuries, Dumbarton Rock became a mighty garrison fortress, its defences packed with guns.

It last saw military action as recently as the Second World War.

Stephen Duncan from HES said: “I’m delighted to announce details of this year’s ticket giveaway, which offers free entry to a host of our winter-opening ticketed attractions over the St Andrew’s Day weekend.

“We’re committed to ensuring that everyone has the opportunity to explore and enjoy our historic environment. If you’ve never visited your local historic site, this is your chance to get out and discover Scotland’s fascinating past for free.”

The public has until 5pm on Thursday, November 28 to register online and apply for tickets to the attraction of their choice.

To apply, go to ticketgiveaway.co.uk