Relatives and sympathisers braved Saturday’s downpour to lay wreaths in London’s East End remembering two teenage brothers and their workmate killed 22 years ago after being overcome by poisonous hydrogen sulphide gas in a sewer.

More than 100 packed Shadwell’s Watney Market off Commercial Road to mark the anniversary of the freak accident in which David Richardson, 19, and brother Paul, 17, died in 1990 with 32-year-old Steve Hammond while working in the sewer beneath the market square. Only a fourth member of the working party survived.

The boys’ sister, Carol Hammond, led the mourners in a minute’s silence in the rain followed by a lone piper playing the lament, which also remembered Stephen Reilly who was killed in another accident the year before, on the giant Canary Wharf construction site.

The sewer tragedy led to protests after the east London construction company involved was fined just �50,000.

At the time, the boys’ father Derek Richardson called for criminal charges. It led to the national Construction Safety Campaign which fought to get Corporate Manslaughter legislation passed in 2007.

The organisation also held a national remembrance service at Tower Hill in addition to Saturday’s Watney Market remembrance, as part of its annual Safety Day commemoration for all workers killed in industrial accidents in Britain.