Leadenhall Market has been closed after an explosion, thought to be caused by an electrical fault, occurred this morning.
A 20-metre hazard zone has been put in place around the City hub and it is not clear when the area will be reopened.
A spokesman told City A.M. it was a "small, localised explosion".
He added: "We were called at 9:21am to a manhole cover that went bang – it didn't affect any buildings, and there have been no injuries.
"We have put in a hazard zone, we have liaised with UK Power Networks who are also on the scene and we will be leaving shortly."