Meanwhile, in London: making use of London’s empty spaces, by the Centre for London think-tank, defines meanwhile use as "a loose designation for activities that occupy empty space, while waiting for another activity on site".
The report says development sites in London "are vacated for months, if not years, before construction begins. And on larger sites, some parts remain empty until the last phase of development".
This leaves vast tracts of land, which could be put to productive use, unused for long periods of time, the report says.
The document says that a key barrier to sites being put to meanwhile uses is the planning system, which can "make meanwhile projects difficult to undertake".
It says the planning system "plays an important role in protecting residents from the negative impact of urban change. But there are elements of the system that make meanwhile use opportunities more difficult to realise, by narrowing the window of opportunity for meanwhile activity".
"The statutory target for dealing with a planning application is eight weeks for a minor scheme, which is met for 85 per cent of schemes. Yet, eight weeks is a considerable wait for meanwhile uses that only have a year on a site", the report says.
It also says that meanwhile options for sites "tend not to be prioritised within local planning departments, given resource constraints and the overriding priority that most attach to increasing housing delivery".
To tackle these issues, the report recommends that London boroughs should "make clear in local plans that they expect landowners applying for planning permission to open up space to meanwhile activity".
It also says the government "should explore allowing more flexibility in temporary changes between use classes to enable more mixed and innovative meanwhile uses through permitted development".
It adds that the government and mayor of London "should explore a flexible and fast-track approach to assessing and ensuring mitigation of any local noise, transport or other impacts from meanwhile use".