Intrigued tourists watch as Paul Doy climbs a ladder outside London's Westminster Abbey and lifts the globe of a gas street lamp.
Winding its timer, he then ignites a small cloth mesh, creating a distinctive soft warm light that illuminates the darkness.
"I like the historical aspect of it," says Doy, "even if it means getting up at 5am to tend to the lamps."
The 200-year-old nightly ritual nearly became history when the local government announced plans to replace 174 gas-powered lamps with eco-friendly LED bulbs.
The plan by the City of Westminster council caused uproar among some residents and heritage lovers, and even sparked a question in parliament. But the council decided to scrap the move. Instead, it will convert 94 other gas lamps which are not protected.
Part of London's DNA
London has more than 1,000 gas street lamps, which were installed at the beginning of the 19th century.
At the time, they were considered a major innovation in a city with dark, dirty and often dangerous streets.
In central London, they still light up parts of The Mall leading to Buckingham Palace, the back streets of Covent Garden, and around Westminster Abbey. The atmospheric light they give out is evocative of Charles Dickens novels, Mary Poppins and Sherlock Holmes.
"They are an incredibly important part of the fabric of London's history," says antiques writer Luke Honey.
"They are in London's DNA."
Watch the video above to find out more.