IMAGINE a boxing heavyweight being able to punch without using much energy - he'd have vast reserves of power and be as lively at the final bell as he was at the first.

The Peugeot 307 flagship, the XSi HDi, is a bit like that. With its re-worked two-litre diesel engine, it's a big hitter, yet uses liquid nourishment sparingly.

This 307 variant stands foremost among family-sized hatchbacks, and heads the 25-strong 307 fleet of three and five-door hatchbacks, selling for £17,220.

Peugeot got together with Ford to come up with the XSi's innards, an impressive and lively re-working of the existing two-litre, 110bhp diesel unit that has already seen good service in the 307.

This latest incarnation of the four-cylinder favourite sees power upped to 136bhp, top speed improved from 119mph to 126mph, all for very little fuel penalty. The 110bhp unit does 54.3mpg on the combined cycle, the 136bhp XSi version returns 52.3mpg.

Technical improvements include an aluminium cylinder head, a new Siemens diesel injection system, and an upgraded turbocharger.

That extra surge operates in the top four of the six manual gears, so it's a dynamic, flexible and fast car that will also tow a heavy load effortlessly when needed, even with the interior packed with bodies and baggage.

The zero-to-62mph sprint, by the way, is achieved in 9.8 seconds.

For all the excellent gains in performance, the XSi remains environmentally friendly, complying with the tough Euro-IV emissions standards.

The subsequent low benefit-in-kind tax liability banding of 16 per cent means company users can have the potency without excessive pocket punishment.

Buyers of the two-litre petrol XSi version, of comparable performance to this diesel, are banded at 23 per cent.

The ride and handling of any of the current Peugeot range is hard to fault, and the 307 is no exception.

Peugeots come into their own as drivers' cars, and the only criticism of the XSi is minor - the view is such that it takes a while to gauge just where the front number plate is, which can make tight parking tricky.

On the open road, though, happily throw it around as you will - it's got the grip to match the go.

With traction control, anti-lock brakes with electronic assistance, a full complement of front, side and rear airbags, it's totally safe, too.

Peugeot says the XSi has sporty trim, but it's certainly more like luxury fittings. The front seats, for example, while leaning towards the racing bucket design, are reminiscent of a favourite TV armchair - they are so comfortable.

The support and padding are simply top-notch, and extended journeys prove just how supportive they are.

The rear space is good, but not so hot where headroom is concerned. Step outside of the 307 and take in the overall design and you'll see why. This car's styling seems to be all about the front half - or two-thirds, if you like - with the rear looking like an afterthought.

But if it's four people and luggage you want to shift, without going for an ultra-tall, mid-sized people carrier, then the 307 is certainly the next-best thing.

Key features of the XSi's repertoire include half-leather trim, cruise control, electric folding door mirrors, automatic wipers and headlights (brilliant on these darker evenings), digital air-conditioning and a trip computer.

For more information, call Viking Peugeot on 01256 697700.