Martin Duncan Allen was a 15-year-old British boy who disappeared while travelling home from Central Foundation Boys' School on the London Underground on 5 November 1979. He was last definitively seen alive at King's Cross St Pancras tube station at approximately 3:50 p.m. walking toward the Piccadilly line platform, although subsequent eyewitness statements indicate Allen may have travelled—willingly or otherwise—to Earl's Court tube station in the company of an adult male.