round 200 people have been evacuated from premises close to Leicester Square after a gas main ruptured.
The London Fire Brigade said two fire engines and around 10 firefighters from Soho and Euston fire stations were called to the scene at around 7am on Tuesday.
Engineers from Cadent gas are working to repair the gas leak while a 50-metre cordon remains in place at the scene.
Station Commander Clive Robinson said: “A gas main has ruptured and around 200 people have been evacuated from surrounding buildings and a hotel.
“Crews are expected to remain on scene throughout the morning.”
The Met Police confirmed it had been called to reports of a suspected gas leak and said “emergency services are in attendance and managing the incident”.
The square is currently closed to pedestrians and people are being told to avoid the area, with significant disruption expected.
Stephanie van Rosse, media relations manager at Cadent Gas, told the Standard: “We were called at 6.30 this morning after reports of a smell of gas and have been on site from just after 7am.”
She confirmed a hotel in the area had been evacuated and gas engineers were working to “isolate a gas service pipe” and vent properties.
Ms van Rosse added the side of Leicester Square cordoned off near the Vue Cinema was “just as a safety precaution, while we carry out investigation work”.
She continued: “The main priority when we arrived this morning was to ensure everybody’s safety.”
Leicester Square is one of central London’s busiest shopping and tourist areas.