What was the car of the Show at Frankfurt? In an eco-obsessed show, the vote was split between two of the smallest concepts with the shortest names – the Volkswagen Up! and the Toyota iQ.

These two tiny cars are likely to define the sort of city cars that will become commonplace within the next decade. They’re not gimmicks – they are genuine, four-seater cars, with the focus on high fuel economy and low emissions.

Toyota has already seized the moral high ground on low emissions with the Prius hybrid, and the iQ – a concept for now, but certain to be built - is likely to feature the same technology, or perhaps the next generation plug-in hybrid system that Toyota is developing, allowing cars to be recharged from any power socket.

It is only 2.98m long – 56cm shorter than a Fiat 500 and only 28cm longer than a Smart. Yet its interior cabin space is almost exactly the same size as a Yaris. “Last year we witnessed a 20% annual increase in small car demand in Europe, showing us the development of small vehicles serves a receptive and growing market,” said Thierry Dombreval, Toyota Motor Europe executive vice-president.

The Volkswagen Up! is a little longer at 3.45m, but still a lot shorter than VW’s current baby, the Fox. Designed by VW chief designer Walter da Silva, it will go into production around 2009, with a low price tag in Europe of around €6,000. A three-cylinder engine should give fuel consumption of around 70mpg. VW hopes it will become a VW Icon– and given the growing eco-consciousness among European consumers, there’s a good chance it will attain the status of the Beetle or the Golf.