See an article by Adam Bienkov published by politics.co.uk in which he looks at some of the cynical ploys adopted to expel homeless people from appearing on city streets and driving them to more marginal areas. He says,
“For years borough leaders and City Hall have worked together to in their words “design-out” rough sleepers from London.
This has involved not just floor spikes, but also sloped surfaces, bench barriers and more.”
See more here