WE have just been helping make motoring history by becoming part of the team carrying out the first circumnavigation of the globe in a hydrogen powered car.

The journey in the Mercedes F-Cell is the most ambitious test of a zero emission vehicle ever staged.

It marks the 125 anniversary of the automobile when Mercedes forebear Carl Benz filed the first patent for an internal combustion engine car and points to the future of everyday motoring.

Our stint in the fuel cell driven Mercedes was across the wilderness of southern Australia - 1,200 miles from just outside Adelaide to the west coast city of Perth.

Already the F-Cell car had travelled from Mercedes' home town of Stuttgart in Germany across Europe and the United States before arriving Down Under.

The stretch across the barren lands of the Southern Hemisphere was regarded as one of the most gruelling for the high tech systems which make the first wave of F-Cell cars tick.

Basically, the F-Cell is a space age version of the Mercedes B-Class compact people mover and while there is little remarkable about the dynamics of the car, the technology is cutting edge.

A fuel cell mixes hydrogen with oxygen in a controlled fashion to produce electricity which powers a motor to drive the car.

The principle is not new. It was used by NASA in the moonshot programme of the 1960s and 70s and its use in cars has been under development since the mid-90s.

Along with Mercedes, Honda, Hyundai and Kia have been paving the way in fuel cell research and General Motors is also working on the technology.

Other car makers - notably BMW and Mazda - have also been experimenting with hydrogen to fuel conventional engines.

The beauty of hydrogen fuel cell cars is that they produce zero exhaust emissions. The only waste product is water - two gallons for every kilo of hydrogen used.

But while hydrogen is readily available as a source of renewable energy, the stumbling block is a lack of infrastructure to feed the cars.

Currently there are fewer than 200 hydrogen filling stations in the world and on our journey across Australia none. To overcome the situation a large gas tanker was drafted in for refuelling en route.

The F-Cell has a range of around 250 miles on a single tank of hydrogen - more than twice that of the battery powered electric vehicles which are now arriving in Britain.

It takes only three minutes to refuel with gas pumped at high pressure into three cylinders housed in the middle of the sandwich floor of the B-Class.

Made of a virtually indestructible composite, the cylinders have been tested to withstand any impact and prevent leakage allowing the F-Cell to be kept garaged or parked up for long periods if necessary.

Fully fuelled the F-Cell caries 3.7 kilos of hydrogen at an incredible pressure of 700 bar - more than 300 times the pressure of an average car tyre - and its fuel load is equivalent to some 2.7 gallons of diesel.

However, the F-Cell is surprisingly economical. Compared to a diesel B-Class which can average around 55mpg, Mercedes says the F-Cell will return the equivalent of 86 to the gallon.

That's very believable. On one leg of our Australian journey we managed to achieve a fuel consumption of 0.96kilos of hydrogen per 100 kilometres which works out to 91mpg - and that was cruising at 70mph.

Overall our F-Cell returned the equivalent of 76 to the gallon on the 1,200 mile trip.

Even allowing for the amazingly straight roads across the Nullarbor plain - you can almost count the number of bends on your fingers and toes - that's a performance which would be hard to beat in the best of diesels.

Temperatures were nudging 30C which meant the air conditioning was running constantly, so theoretically there was more economy to be had.

Driving the F-Cell is an unusual experience requiring slight adjustments to your style to get the best from the car.

On start up it is utterly silent. All you notice is warning lights illuminating on the dash while the car is powered up from a lithium ion battery housed under the boot floor.

Seconds later the fuel cell whirs into life, its state of readiness indicated from a dial in the instrument cluster.

Although the F-Cell looks very much like a conventional B-Class, inside there are subtle differences - mainly to the instrumentation with the rev counter being replaced by a boost gauge showing the instant power demand in kilowatt/hours.

The centre display screen can be configured to show a graph of the electrical performance or the flow of power from either the cell or the battery to the motor. There is also a clever graphic which represents atoms passing through the cell and the resultant water coming from the exhaust as vapour.

The available range is shown digitally on the dash and you find yourself watching that like a hawk. The figure varies wildly depending on how you use the accelerator.

Power off to go downhill and regenerative braking will boost the battery and the range will increase in an instant.

On an almost full tank we saw the range fall from around 220 miles to 140 then recover to 210 in a matter of only a few miles.

Initially it is quite worrying. A more accurate figure is available from the digital fuel gauge which shows exactly how much hydrogen remains - but then you have to do the sums yourself to work out how far you can travel.

Warning lights will illuminate if you get dangerously low and non essential systems will shut down automatically to save energy, while the car has a range of around three miles on pure battery power.

There are only two gears - forward and reverse - and while the moving off takes place under battery power the fuel cell kicks in as speed builds, although the changeover is unnoticeable.

Electric cars are fun to drive with the power available on demand.

Press the accelerator hard and you take off in an instant. The F-Cell may have the equivalent of a 136bhp engine but it has the torque of a super car.

Top speed in the F-Cell is slightly over the ton and the 0 to 60 time around 11.4 seconds but  the kick from the throttle is not as marked as it is in a battery powered EV.

That's because you are actually making the electricity when you push the throttle, not simply taking it from stored energy in a battery. There is a definite lag, albeit slight, between the request from the accelerator and the hydrogen being released to create power.

Release the throttle or stop in traffic and the fuel cell cuts out immediately, conserving fuel and running the car's systems on battery power.

Once you get to grips with the quirks, the appeal of hydrogen grows and grows. It is very much like driving an everyday car except there is no pollution and it's completely silent.

The fuel cell used in the F-Cell is a huge improvement over the system Mercedes used in experimental A-Class models more than 10 years ago.

It is 30 per cent more powerful, 40 per cent smaller and 30 per cent more economical.

More importantly it can now operate in temperatures as low as -25C and although the car weighs some 300 kilos more than a conventional B-Class, the race is on to refine the system.

The F-Cell demonstrates the technology can be fitted to a standard model with minimal compromise and the plan must be to make fuel cell power available in other models across the Mercedes line up.

On the F-Cell the entire fuel cell system is housed under the body or below the bonnet meaning the cabin and boot are the same size as on a regular B-Class.

Mercedes is very serious about fuel cells as the power of the future and in limited numbers the F-Cell is already in the public domain, leased to 21 drivers at around £700 a month in either Los Angeles or in Germany where there are hydrogen pumps available in a few cities.

A small production run is moving into gear with the car likely to be priced in the low £30,000s.

Where hydrogen is available it costs the equivalent of about £3 a litre - twice as much as diesel - but costs should fall if demand grows.

As we passed the halfway point on the world tour the F-Cell had clocked up more than 10,000 miles in two months and not missed a beat, proving that fuel cell technology is a viable alternative.

The journey is due to finish in Stuttgart early in June by which time the car will have covered some 20,000 miles covering four continents and passing through 14 countries.

What Mercedes and the other car makers involved in developing hydrogen cars need now is support on the political front.

It sounds a familiar story and will not be an easy journey. Already we have seen only minimal provision of LPG and biofuel pumps and the arrival of electric charging points in some cities is very much in its infancy.

While the technology is available there is still a long way to go before we really encounter the end game for the internal combustion engine.