Bioethicist and public health scientist, Dr Evie Kendal, from Swinburne University says hostile architecture refers to design choices intended to influence social behaviour, often with the goal of discouraging certain activities or people in particular areas.

She says classic examples include ‘skate stopper’ bolts on surfaces to prevent skateboarding, or arm rests on benches that stop people laying down.

“What is often most insidious about this increasingly prevalent design practice is how the choices can appear neutral – or even decorative and appealing – unless you are the target for exclusion,” Dr Kendal said. “Sloping benches and large flowerpots on the streets may look artistic, but they can intentionally remove safe resting places for rough sleepers.”

However, she says interventions targeting a certain group can have knock-on effects for others. For example, designing public benches in a way that discourages ‘loitering’ also means elderly people may struggle to find appropriate places to rest when they need.

“Restrictions to open public spaces also impact travelling populations, with the placement of bollards and other obstacles preventing camping and caravan parking,” she said. “The goal may be to ‘move on’ these groups to fee-paying alternative sites, or to prevent large gatherings of people.”

Dr Kendal said that, in many cases, avoiding the formation of homeless encampments in these areas may also be a specific objective.

“As with all hostile architecture, some behaviours are being classified as ‘undesirable’ and targeted for modification, and these tend to be those that challenge commercial interests in these spaces,” she said. “If recreational vehicles are forced out of publicly available sites, the owners will have to pay to access private facilities instead.”

Dr Kendal says the cost-of-living crisis mean more people are relying on temporary accommodation, but free and low-cost options are limited.

“For people living in mobile homes, restrictions on available spaces to park or camp suggest they are not welcome in these places and are being pushed to the side,” she said. “As with people experiencing homelessness the attitude of those engaged with hostile design seems to be ‘out of sight, out of mind’.”

• Have you noticed any examples of hostiile architecture on your travels? Comment below.