It is usually treats and offers surrounding supermarket checkouts that end up burning holes in our pockets – but now it has been revealed that shopping trolleys themselves could lead to us spending more.

A study has found that removing the horizontal grip bar on trolleys and replacing it with handles like those on a wheelbarrow could boost sales by 25 per cent.

Researchers from City University of London’s Bayes Business School and the University of Innsbruck, in Austria, tested a new trolley design based on psychological research.

The research “has proven that triceps activation is associated with rejecting things we don’t like – for example when we push or hold something away from us – while biceps activation is associated with things we do like, for example when we pull or hold something close to our body”.

Prof Zachary Estes and Prof Mathias Streicher used the changed trolley design to survey 2,359 shoppers over three days. They discovered that people using it bought more products and spent 25 per cent more than those using standard trolleys.

The findings indicate that retailers are likely to chalk up greater profits by providing customers with trolleys with parallel handles, while people are likely to exercise more control over their spending if they are using a standard trolley. The researchers have held talks about the findings with leading supermarket chains in Austria and the US.