Families of six men killed in an oil tank explosion have gathered to mark the 50th anniversary of the disaster.
The Dudgeon's Wharf tragedy led to changes in legislation and improvements in how firefighters deal with chemical incidents.
Crews were called after a fire broke out at an oil storage tank on the Isle of Dogs on July 17, 1969, while demolition work was taking place.
Although employees at the wharf had managed to put the fire out, firefighters arrived to make sure it was safe.
Instead, the tank exploded.
Five firefighters were killed - Michael Gamble, Alfred Smee, John Appleby, Terence Breen and Trevor Carvosso - along with construction worker Richard Adams.
The explosion remains the largest loss of life experienced by the London Fire Brigade in a single incident since the Second World War.
Mr Breen's son Terry, who was five at the time of the explosion, gave a short reading at the memorial service.
The 55-year-old said: "Dad had been in the Brigade 12 years when he was killed and my mum was left with me and my two brothers. It affected us all in different ways.
"He was a fantastic family man and we are all incredibly proud - you can't not be proud of someone that has served in the Brigade.
"I'm always thankful we are able to mark the anniversary. It's so important not to forget and to always honour their memory and we were very proud to be part of the service."
As a result of the explosion, there were changes to legislation and a strict code of practice now controls the removal of tanks which have contained flammable substances.
It also influenced the development of the Hazchem code in the 1970s, meaning all known chemicals were allocated an identification code to help firefighters when dealing with chemical fires or spillages.
London Fire Brigade assistant commissioner Andy Roe said: "The changes implemented following this incident have been used worldwide undoubtedly helping to protect firefighters all over the globe, meaning that the loss of life on that terrible day has not been in vain."
As part of the service, led by the Bishop of London Sarah Mullally, a plaque was also unveiled by the Fire Brigades' Union in memory of the firefighters.
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