A CRACKED windscreen on the A4 has left me cursing the state of our roads. I saw the marble-sized pebble arcing up from the wheels of a juggernaut coming the other way, and it hit the glass with a bang like a rifle shot.

A six-inch crack appeared which subsequently spread across the screen - isn't it always exactly in your line of sight?

This coincided with a puncture in the offside front tyre, leaving me with no option but to explore Peterborough's fast-fit outlets.

First-off, the screen: contrary to what I was expecting - a long delay in sourcing the glass owing to the newness of the A4 - not only did Autoglass have a new screen in stock, they could have a mobile unit despatched to our office car park the next day. The work was completed within a couple of hours using a genuine Audi screen - a slick service that caused not the slightest inconvenience. I was expecting a hefty bill for the new glass, and at £260.71 it was not cheap, though I suspect that is the going rate. Interestingly, Autoglass was quoting a 15 per cent discount for RAC members and 35 per cent off if you belong to the AA.

With any puncture that renders the tyre useless, I'm always keen to ensure the exact same make and model of replacement is fitted, and ATS was able to oblige with a new Michelin Primacy 205/55 R16.

Unusually, the Audi spare is a full-size alloy so I left the puncture with ATS for renewal and ended up with two brand new tyres on the front and the good original as the spare.

After almost 16,000 miles, both fronts were a little more than half worn, which suggests a life of about 20,000 miles - not bad considering the Audi's 180bhp quattro transmission with front-drive bias. The rears, by contrast, look good for at least 30,000 miles.

ATS charged about £125 for the replacement tyre, including balance, valve and VAT - competitive considering its performance specification.

Otherwise, things have been as faultless as ever with the A4. I'm always impressed by the TDI's fuel consumption, which now easily exceeds 40mpg on a moderate run.

In sixth gear, the engine is turning over at only 2,000rpm, making for relaxed cruising, and allowing you to enjoy the superb Bose sound system - a great-value £460 option. For this, you get 10 speakers and six amplifiers, giving concert hall sound quality.

Yet when it is time to 'press on', there's no better companion than a quattro. This is where the TDI's mid-range flexibility comes into its own, with the close-ratio gearbox really matching the engine's delivery. Together with the quattro's grip and traction, the A4 makes for a formidable and entertaining sports saloon.