This week Southern Gas Networks starts a programme of roadworks around Borough Market and Southwark Cathedral which will last until early December.
Southern Gas Networks says that the existing metal gas mains and services in Winchester Walk, Cathedral Street and Montague Close need to be replaced with modern plastic polyethylene pipe to ensure a continued safe and reliable gas supply.
The second phase, also due to last about three weeks, will mean that Cathedral Street is closed to through traffic.
In phase three, due to last approximately eight weeks, Montague Close will be shut.
To allow room for the manoeuvre of equipment and ensure everyone's safety, it is necessary to temporarily close sections of these roads around the work areas. Only one road closure will be in place at a time and signed diversion routes will be in place for motorists.
"All our work is being carried out in close consultation with the London Borough of Southwark, Transport for London, Borough Market and Southwark Cathedral," said SGN construction manager Craig French.
"We will be doing everything we can to reduce disruption and we will ensure pedestrian access to Borough Market and Southwark Cathedral is maintained at all times. More information about this project can be found in our customer information leaflet.
"I would like to apologise for any inconvenience that may be caused by our work. We understand that people can get frustrated by roadworks; however, the new plastic pipe has a minimum lifespan of 80 years.
"This means that when the work is complete, local residents will continue to enjoy the benefits of a safe and secure gas supply for years to come."