It might not look like much, but the Magic Carpet Car Wash in Dundalk, Ireland, is the kind of business economists should study. I visited earlier this year when doing research on the Irish border and the trip stuck in my mind.

Unlike the car washes I remember as a kid, in which robotic bristles descend and scrub the car clean automatically, this one was staffed by workers. On the forecourt were two men from Eastern Europe spraying cars with power hoses. On the other side of a fence, two electricians were installing a system that would replace the workers I had just seen.

According to Killian Cawley, of PE Services, the car wash was responding to a drop in the supply of cheap labour. Dundalk is close to the border in Ireland, and, just like many British regions, it has seen a fall in the influx of foreign workers since the Brexit vote.

The Magic Carpet Car Wash model had relied on cheap labour that was drying up. So, in a textbook case of productivity improvement, it had called up PE Services and made a capital investment.

The kit PE was installing was simple – a set of pipes and sensors that would spray the car as it passed through. But it would reduce the workers needed from 10 to four while doubling the speed at which cars could go through.