Firefighters were called to a gas leak at a restaurant and office block on St Paul’s Churchyard.
A gas main was leaking into a basement. Around 30 people were evacuated from St Paul's Cathedral and a further 200 people were evacuated from commercial premises in the area. A 25m cordon was in place as a precaution.
The Brigade was called at 1320 and the incident was over for firefighters by 2313. Two fire engines, two fire rescue units and support vehicles were at the scene.