When the management of a block of luxury flats in London felt they had an issue with homeless people sleeping on the doorstep, their solution was apparently to install a set of spikes that were later branded "ugly, self-defeating and stupid" by Boris Johnson.

The Mayor faced criticism himself for not doing more to deal with the growing number of people sleeping rough in the capital – so perhaps he could look to the work of a charity in Vancouver for inspiration.

RainCity Housing, which provides specialised accommodation and support services for homeless people in the Canadian city, has set up instant pop-up shelters that take the form of an ordinary park bench.

During the day, the innovative design simply works as the back support to benches where people might sit and eat lunch or while waiting for a bus.