A 20 mph speed limit is to be introduced on all streets in the Bankside area by the end of March 2014, Southwark Council has revealed.
Large swathes of SE1 to the south and west of Bankside already have 20 mph speed limits.
Last November Southwark Council assembly passed a motion in support of a 20 mph speed limit on all borough roads.
The new 20 mph zone in Bankside will be part of a phased approach to reducing the speed limit on roads which don't already have a 20 mph limit.
The new signage in the Bankside area has been funded by Transport for London to the tune of £256,000.
The council says it will cost a further £1.1 million to extend 20 mph signage to the rest of the borough.
20 mph limits are to be introduced on a 'signage only' basis, with physical works to be carried out later where there is clear evidence that the limit is regularly flouted.
Southwark Council has written to the Association of Chief Police Officers calling for a change in national guidance that officers should not carry out routine enforcement of 20 mph limits.
"The council is convinced that implementing a borough-wide scheme has the potential for road casualty reduction, will have positive impacts on sustainable travel such as walking and cycling and help to improve air quality," wrote Cllr Barrie Hargrove, cabinet member for transport, in his letter to ACPO.
He added: "I would, however, call on ACPO to encourage their members to commit more resources for the enforcement of 20 mph speed limits and to engage in more meaningful dialogue with local highway authorities."
The proposed borough-wide 20 mph speed limit excludes major roads which are managed by Transport for London rather than the council.