Americans and Europeans are ready to buy the same cars. That was the unshakeable view of engineers and planners that emerged from the Detroit Motor Show; and that makes it inevitable that within a few years there will be American-made mass- market cars on sale in the UK.

The first reason is that Europeans are upsizing while the Americans have been so shocked by a $3-gallon (the equivalent quantity is $9 in the UK) that they are downsizing.

Secondly, Rick Wagoner and Alan Mulally have said it must happen. These two guys run financially imperilled companies. Wagoner at GM is in a slightly better position than Mulally at Ford who is probably a year behind in the scramble for financial stability. But both have told manufacturing departments the same thing: no more duplication of platforms. Replication is the name of the game.

Within eight years – the time it takes to renew the whole range of B, C and D segment models – cars sold on both sides of the Atlantic will be the same. The Ford Focus will be the same Ford Focus in the US – not something that has the same name with difference construction, performance and style as is now the case.

GM does it already with the Vauxhall Astra which also sells as a Saturn Astra and does perfectly well.

Ford says that new Fiesta, then Focus, then Mondeo – the order in which they are due for renewal – will get the treatment. The implication for UK dealers is that they will probably get more derivatives of new models, and sooner.

In the case of Fiesta for example, the principal market for the hatchback will be Europe, a big target for a three-box saloon will be the emerging markets, and a crossover mini-MPV has considerable van-style relevance at the budget end of a downsizing US market.

Ford and GM will both want to build their cars closest to the point of sale, but the derivatives required in low volumes will have to be shipped.

The Fiesta crossover is bound to be built in the US. It would not be built in Europe unless there was demand for 100,000 or more.

The four-door saloon – principal choice of the emerging markets – could ship to Europe from eastern Europe and be made in the west if the volume criteria was met. The car is so pretty that it should become a western Europe home-build from the off.

Ford will hope and expect to be able to build all derivatives for its huge home market and then export some to Europe while currency demands that they should.

How odd it will be to get a small car in Motherwell made in Motown? And how much stranger if it was decently built. Planners concede that has been an issue, but that even JD Power now has to recognise that the US has started to narrow the gap. Within two years, it should all be out in the open, and the transatlantic car trade should be in full swing.