Rotherhithe Tunnel carries over 34,000 vehicles per day
All traffic will be diverted over Tower Bridge every night between 9pm and 6am.
The closure is necessary so that Transport for London can undertake major improvements to the tunnel bore.
These include installing a state of the art communication system and replacing loose, damaged and discoloured tiles.
The tunnel is closed every Monday night routinely to carry out regular maintenance operations which include testing emergency equipment, changing lighting units, cleaning the tunnel lining, sweeping the carriageway and footways, structural inspections and emergency repairs.
Rotherhithe Tunnel is 1.481km long and opened to traffic in 1908.
It is an 8.23m diameter single bore tunnel, with a single lane of traffic in each direction and two footways.
It was originally designed to carry horse-drawn carriages and pedestrians; but now carries over 34,000 vehicles and 20 pedestrians per day.