Back in 2008 I was working for Lambeth Council at the Shakespeare Road depot and the bloke opposite me was working on a couple of schemes. One was a Community Toilet Scheme. If I recall rightly he was having great difficulty getting businesses to sign up to open up their toilets to the public (for an annual fee) and McDonalds were one of the few companies in Brixton who agreed to take part. Not sure if the idea was very well marketed though.
Seperately he was working on pop-up toilets. There were two being piloted. One, I believe was in Electric Avenue. Don't know if that scheme was a sucess or not.
The background to both of these schemes is that was ajudged too expensive to address the shortage of public toilets in Brixton with attendants. Unattended toilets were considered too vulnerable to anti-social behaviour.
http://www.ukbusinessgrants.org/Community-Toilet-Scheme---Lambeth.php
http://brixtonhill.blogspot.co.uk/2009/01/community-toilet-scheme.html