A multi-million pound appeal was launched today to secure the future of the Black Watch's historic home.

Regiment trustees are purchasing Balhousie Castle, in Perth, from the Ministry of Defence and planning its redevelopment.

They say the expansion of the castle, which houses a museum, will ensure that the history of The Black Watch is preserved for future generations.

More than £3 million is needed to develop Balhousie, which dates back to the 15th century, according to organisers of the Black Watch Heritage Appeal.

Appeal president, the Earl of Airlie, said: "The Black Watch is one of the most famous regiments in the world and the Red Hackle symbolises all its many achievements.

"We must ensure that these achievements are recorded for posterity and this appeal for funds will enable us to do so."

The Black Watch, which first saw battle in 1745, is famous for the red hackle worn on soldier's caps.

In 2006 it was merged with other Scottish infantry regiments to form the Royal Regiment of Scotland.

The title of the battalion is now The Black Watch, 3rd Battalion The Royal Regiment of Scotland.

It was recently announced that troops will be posted to Afghanistan's Helmand Province in April next year.

The regiment museum in the grade B listed Balhousie Castle, which overlooks North Inch and the River Tay, is a popular visitor attraction.

Trustees want to providing more space for new displays and better tourist facilities.

The purchase of the castle is expected to be completed by the end of 2008, with the planned improvements carried out by 2010.

Perth provost Dr John Hulbert said: "Perthshire is the heart of the recruiting territory for the Black Watch, and Perth is its spiritual home.

"For many years now, Balhousie Castle has provided a meeting place and a memory bank, a museum for artefacts, and a place where archivists and conservators can work on the huge volume of material associated with the regiment.

"It is right that the future of Balhousie Castle should be secured for the Black Watch, for Perthshire, and for Scotland."