What car should I buy?

**I commute a total of 960 miles a week and want to buy a small, low tax, diesel-powered car.

I've been looking at the Smart Fortwo diesel, or possibly a Ford Ka 1.3 TDCi, mainly because of the promise of high mpg. However, with an average yearly mileage just shy of 50k, I'm a bit worried these cars won't last three years.

At the moment I own a diesel Mondeo that qualifies for the scrappage allowance, so I'm only looking at brand new cars that costs less than 10k (I have 8k to spend).

What do you think - will either the Smart or Ka be suitable for my needs? Any other ideas?
Paul Edwards**

The Smart Fortwo, in particular, isn't suited to long distances and high-mileage driving. Yes, it's officially the most economical car currently on sale, but it is only really suited to city driving. As well as a very weedy 45bhp engine, the Smart is poorly refined and short on safety kit. The ride is very bouncy, too.

The Ka is a better bet, although it doesn't ride particularly well, either, and it's pricey for what it is.

Its big brother, the Fiesta, isn't much more expensive, but is a much better and more refined car. The entry-level 1.4 TDCi Studio costs 11,595, but some shrewd haggling should bring the price down to around 10,300. That's before your scrappage allowance.

The Hyundai i20 is another option. It's cheaper than the Fiesta, and the 1.4D 74 Comfort is better equipped. It also comes with a five-year, unlimited mileage warranty. Push for a price of 8239.