Poorly managed grey fleets are “a timebomb waiting to blow up in bosses’ faces”, warned Diarmuid Fahy, head of risk management at ING Car Lease.

An ING survey of medium sized fleets found that while only 20% took measures to monitor employees who opt for cash-for-car programmes, 18% admitted to not having a risk management policy at all.

In total, just 30% of businesses said they took account of private vehicles in their risk policies.

“This blind spot the fleet industry has for private and cash allowance drivers is a real issue for businesses,” said Mr Fahy.

“We want to see more companies treating cash-takers in exactly the same way as company car drivers…

"We are calling for a step change in culture where grey fleets are treated in the same way as company cars.”