Thinking of buying a used Land Rover Defender? Al Suttie offers advice in the 80th anniversary edition of GEM Motoring Assist's Good Motoring magazine.

The original workhorse and warhorse, the Defender can trace its ancestry back to the first Land Rover of 1948.

Due to be replaced in 2018, production finishes at the end of this year but it remains one of the most versatile and able off-road vehicles you can buy. Not the most refined but definitely the original go-anywhere 4x4.

While its rugged charm holds the key to much of its appeal, Land Rover fettled and finessed the Defender throughout its life. The best models are the most recent, delivering reasonable on-road manners alongside legendary terrain-busting off-road ability.

For most buyers, a May 2007-on Defender is the best choice as it received a 2.4-litre turbo diesel engine, from then-parent company Ford, and a six-speed manual gearbox. It's a Transit van unit producing 120bhp and 266lb.ft of low-down shove for pulling the car through mud. A 2.2-litre unit replaced it in August 2011 with lower emissions and improved economy. Defenders with these engines are identified by the extra bonnet bulge.

What to look for

Defenders are hard-working and many will have been used off-road. This takes a toll on the most hardy 4x4. Get underneath to check the chassis for dents, scrapes and possible rust. While there, inspect the engine, transmission and differentials on front and rear axles for oil or fluid leaks.

The suspension will feel quite firm on road but this is normal. So are a few creaks from the bodywork and interior, but check both are in good condition. Defenders are often used for towing, so make sure the brakes work smoothly and stop straight.

Towing puts strain on the clutch and gearbox so check every gear, including reverse, engages easily. Accelerate hard in lower gears to be certain there's no slip from the clutch. Engage the low-ratio transfer box to make sure it works properly as it is key to the Defender's superb off-road driving skills.

Both engines should pull strongly without any stutters. A diesel particulate filter was fitted from 2012, so make sure the exhaust is free of black, sooty smoke and avoid any car used for repeated short journeys as this destroys the filter.

Which one to buy

There's nothing to choose between the two diesel engines on offer, so it comes down to condition and which body style best suits your needs. For off-road work, the shorter Defender 90 is more nimble and can still tow up to 3.5 tonnes of braked trailer.

The longer Defender 110 provides much more cabin space and seating for up to nine. This is an alternative to a multi-purpose vehicle with the advantage of a huge load area. Other body styles include pick-ups and crew cabs but these are likely to have been commercial vehicles.

How much to pay

A 2007 Defender 90 with rear windows and seats will start from around £12,500 in good order, while a 110 model is another £1,000. A nearly-new model, with all the bells and whistles, comes in at up to £40,000. Uprated versions from the likes of Kahn or Twisted can fetch up to £80,000.