'Suddenly my eyes and throat started burning': what caused Birling Gap's toxic cloud?

Last August, holidaymakers in East Sussex fell ill after a poisonous yellow cloud spread across the sky. What was it, and where did it come from?Mark Sawyer has worked for the Royal National Lifeboat Institution for nearly 30 years, and since 2001 he’s been the full-time coxswain at the Eastbourne lifeboat station. Shortly after 5pm on the Sunday of a bank holiday weekend last August, he received a report from the coastguard in Southampton about an incident at a beach seven miles west of h