Historic stones once used to protect US Open golf champion Graeme McDowell's home golf club from possible IRA attacks have been put up for auction. It is believed the stones may have originally been removed from the Giant's Causeway in Co. Antrim.

The seven hexagonal basalt column stones spent almost 35 years outside the Rathmore clubhouse at Portrush Co. Antrim before being sold last year. The stones were purchased by the club in 1974, they were then placed between the car park and locker rooms to prevent possible sectarian attacks. Last year the club decided they no longer required the stones and sold then to man who planned to use them for landscaping his garden. He has since sold them on and now they will go up for auction next week.

Next Tuesday the stones will go under the hammer in Billingshurst, West Sussex with an starting price of £10,000 ($15,000).

The Giant's Causeway, Northern Ireland's top tourist attraction with 750,000 visitors a year. The historic site comprises a collection of large circular basalt columns which date back to the 17th century.