Expert Blog

We’re stuck between the metric and imperial worlds

When, as a kid in the 1970s, I first noticed the strange inner gauge with the inflated numbers on the speedometer of my dad’s new car, I asked him, as I always did with anything in the car, what it was for. My dad, who was a civil engineer, explained that it measured speed in kilometres per hour, and that kilometres were used instead of miles on the Continent. At first, I thought this meant that on the Continent the car would drive almost twice as fast.

When it was patiently explained to me that a kilometre was in fact equivalent to 0.621 miles, I then felt sorry for Continental drivers as their distances were so small and complicated and their speeds so tricky. Fancy having to drive at no more than 112.654 kmh instead of 70 mph!

The dual speedometer was appearing in UK cars not to encourage UK drivers to visit Europe – that kind of thing was still strictly for bohemians – but because, back in the 1970s, the UK was still supposed to be, officially anyway, heading towards the shiny new platinum future of full metrication, and from 1977 all UK registered cars had to have a speedometer capable of displaying both imperial and metric.

Back in the 1960s, engineers like my dad, fed up with our feudal weights and measures system, and manufacturers, concerned that their main market was no longer the jolly old Commonwealth but Napoleonised Europe, had pressed for change. In 1965 the Labour Government of Harold Wilson, full of enthusiasm for the ‘white heat of technology’, had announced its intention to abandon British Imperial measures, implemented and standardised in 1824, and adopt the metric system – with road conversion taking place in 1973.

This, as you may have noticed, didn’t happen. The Conservatives won the 1970 election and this new-fangled socialist road metrication nonsense was quietly parked and eventually allowed to be forgotten. No administration since, of whatever stripe, has had any enthusiasm for it. Those dual speedometers in our cars are a constant reminder of a more rational future that failed to arrive.

But we didn’t really stay in the past either. In the 1980s fuel sales were switched to litres instead of gallons. Though, of course, odometers remained in miles, and most quoted consumption figures remain in miles per gallon. To add to the fun, regulations on emissions, which have become increasingly important of course, are metric (g/km).

Hence UK motorists in the second decade of the 21st Century move through a twilight world that is neither quaintly imperial nor usefully metric – just a daft, unintelligible blur of both, with no destination in sight.

Horribly symbolising this, from last year, road signs showing height and width limits were required by law to also cram in metres and centimetres as well as feet and inches (this had previously been optional). Good luck reading those at speed – and getting them the right way round.

Alas, this was not to soften us up for full metrication as some pints and pounds fetishists feared – there are still no plans for it – but rather an attempt to reduce the embarrassingly large number of foreign metric lorries getting stuck under imperial bridges.

So we now have an incoherent bi-lingual weights and measures mess where road design and construction, as well as car design and manufacture, are now metric, but distances and speed and weight restrictions are imperial, with width and height restrictions in imperial and metric. Tachographs and speed limiters are metric, and so are motorway emergency markers, and car manuals. But distances and speed limits for road vehicles are only in imperial.

Surprisingly, possibly shockingly, there are however kmh signs on our roads right now. The light railways built in the last thirty years, such as the Tyne & Wear Metro, the Docklands Light Railway and the Manchester Metrolink operate entirely to metric standards – and speed limit signs for trams running on public roads have a nice black-and-white diamond around them to avoid confusion. And panic amongst the little Englanders.

Britain is now the only country in Europe or the Commonwealth that still defines road speed limits in mph. Metrication advocates argue that not only is the UK out of step with pretty much everyone except the US, but that metric speed limits offer a more versatile range of speed limits – because, as I learned as a kid, a kilometre is less than a mile.

Our colonial cousins Australia and Canada took the plunge and successfully switched back in the 1970s; when we said we were going to, but then got cold feet. And in 2005 the Republic of Ireland completed its transition.

And, of course, we’re completely out of step with the US anyway. The US is a vast country and the most powerful and wealthiest one in the world, so it can do pretty much as it pleases. The UK isn’t and can’t. Besides which, American measurements aren’t actually imperial – the War of Independence predates the 1824 British standardisation that created imperial units. So their gallons, for instance, are 17 per cent smaller than ours. (But don’t try telling them that.)

And the good old British mile is of course actually Roman – the mille passus – and imported back into Britain by (the French) William of Normandy. Not to mention that British scientists and engineers such as Newton, Watt, Joule, Faraday and Kelvin contributed to the metric system.

It’s well past time we gave up our imperial pretensions and renamed our weights and measures ‘British Parochial’. Or just pulled our finger out and finally metricated our road system.

- Mark Mason is a journalist, writer and broadcaster.

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