An award-winning jeweller is offering a 'one-off' diamond necklace as a prize to support a charity close to his heart.

Former Old Otliensians rugby player and Prince Henry's Grammar School student Tim Swann came up with the idea as a way of boosting the money he is raising for Brain Tumour Research & Support.

Tim, who learned his trade in his hometown of Otley and is now MD of Form Bespoke Jewellers in Chapel Allerton, is already preparing to run the Manchester Marathon for the charity in honour of his mother, who died of brain cancer.

But he also wanted to put his professional skills to good use and so came up with the idea of designing a piece of jewellery that anyone who makes a £20 donation, and then guesses what his marathon finishing time will be, could win.

The necklace, worth £559, is a diamond-set, white gold 'marathon pendant' with a total diamond weight of 0.265 carats - one for each mile Tim's set to run.

He said: "At 40 I'm too old to play rugby anymore, but not quite ready to hang my trainers up yet.

"I've decided to put myself up for Manchester marathon on April 28 and at the same time raise some money for an amazing local Yorkshire charity.

”I hope this idea will appeal to people. This is a completely one-off design and one that won't ever be replicated.

"I met Carol Robertson, the founder of Brain Tumour Research and Support across Yorkshire, and she told me how she has taken the charity from just an idea to the amazing organisation it is today.

"Over ten years the charity has gone from strength to strength with the support, help and determination of trustees, supporters and incredible patients.

“So much has been achieved but it's the tip of the iceberg for Carol’s ambitions.

"I hope to help her raise further funds to help her to continue her work."

Anyone wishing to enter should visit just-keep-running-just-keep-running to make a donation and guess what Tim's finishing time will be.