Two amateur drivers spent 25 days behind the wheel of the Honda Civic Tourer 1.6 i-DTEC, which recorded an average of 100.31 miles per gallon.
Fergal McGrath and Julian Warren stopped a total of nine times to refuel during their journey, which equalled the distance of driving from the UK to Australia.
The car, which was a standard model without any modifications, achieved an average of 1,500km on each tank of diesel, a fuel cost of £459 in average UK prices.
McGrath and Warren, both members of Honda’s European research and development team, set off from Aalst in Belgium on June 1 to navigate the continent in a clockwise direction.
They returned to the start point on June 25 having exceeded the Tourer’s quoted efficiency — 74.3mpg — by more than 25%.
The drivers will be presented with the Guinness World Records title for ‘Lowest fuel consumption — all 24 contiguous EU countries (all cars)’ at Honda in Swindon, Wiltshire, today.
McGrath said: “It was tough, but we really enjoyed it, and setting this new Guinness World Records title has made all of the hard work worthwhile.”