IT’S hundreds of years old, yet Oxford Castle is embracing a new technology fad in its latest promotional stunt.

Oxford Castle Unlocked is planting 12 vintage keys in ‘geocaches’ across the county – an activity where people try to hunt hidden containers, called geocaches, using global positioning co-ordinates from satellites (GPS) and clues.

Each of the 12 keys will represent free entry to the castle – and according to the esoteric game’s rules, anyone who uncovers the geocache and finds the key must replace it with a new item.

The outdoor treasure hunt has been around for a while, but it has become increasingly popular as smartphones with inbuilt GPS become more common.

Castle general manager Michael Speight said: “Geocaching is a rewarding, fun and free activity which all ages can enjoy and the adventure and discovery aspect of the activity translates perfectly to Oxford Castle Unlocked’s visitor experience. We’re challenging people across Oxfordshire to get involved and find our hidden geocaches, before being rewarded with a fun free day out at the castle.”

The activity was devised by the Castle’s Ellie Stokes, after she tried her hand at geocaching in Winnersh, near Reading.

She said: “When I first started here one of the things that came up was that a lot of people don't know we are here, we are almost hidden in the city centre.

“We also tell people about Oxford’s hidden history so it occurred to me if we hid these geocaches it would all link up perfectly with the idea behind the attraction.”

The locations have been chosen and the keys will be hidden ready for the beginning of May, when the challenge starts. Five will be within Oxford itself, and the locations have been specifically chosen to relate to the 1000-year-old prison’s history. Clues to the hidden treasures’ whereabouts will be posted on geocaching.com and at oxfordcastleunlocked.co.uk Miss Stokes said: “It’s a nice little trail and hopefully people who visit will learn about it and want to explore Oxfordshire further.”

She anticipates all 12 keys would be found within the month.