Daniel Spargo-Mabbs passed away at the age of 16 and Fiona travels the UK delivering drugs education programmes in schools.
The pair of trainers are used by the charity, set up in her son’s name, as a training tool when it delivers workshops to youngsters.
They have not been seen since Friday when Fiona left them on a train traveling between East Croydon and Victoria.
Picture courtesy of the Daniel Spargo-Mabbs Foundation