Not particularly pertinent to the question since UK speed limit road signage has not changed in terms of units (a;though as mentioned Irish signage has), but remember that Keeping Up Apperances was filmed mostly in the early 1990s, 1990 to 1995 - it’s near on 20 years ago!
It’s illegal here (or at any rate, not legal) for public bodies to erect speed limit and distance signs in the metric system.
Current manufacture speedometers have kilometres inside of (and much smaller than) the MPH scale. It’s not legal to register a car who’s speedometer reads in kilometres only.
Yup, all metric now. You can travel slightly faster around town, main roads and motorways, the speed limit being rounded up to kph. A slightly redundant limit is in place on country roads where you’re not allowed to drive any faster than seems physically possible.
The signage they have is quite ugly and harder to read compared to the UK’s. I say that having struggled from the border to Cork via Dublin.
ETA, is the UK’s mph signage and use of pints on packaging the result of any special dispensation from the EU?
Even Canada’s not all metric. It seems (haven’t looked at official publications, though) that the CSA gives all safety requirements in Imperial units. I visited a Toyota plant (metric country, right?) in Cambridge (Canada, metric, right?) and the obligatory safety tutorial was all Imperial. At my company’s own plants, everything for the employees is Imperial, although we’re a metric company (really, our cars, tooling, everything, is metric). When I was living in the greater Toronto area for a year, I couldn’t order a half-kilo of smoked ham at the deli counter in the grocery store, but they sure as hell knew what a pound was. Oh, the 7-Eleven sold US Gallons (not Imperial) of milk in regular, US jugs. Apple orchards were letting us self-pick by the bushel. Roadside stands where selling produce by the pound. Coworkers were talking about miles-per-(imperial)-gallon.
Yeah, we in the United States are just as metric as Canada where it counts. Road sides are arbitrary. Commerce in the USA is metric-enough, and that’s where it’s important.
Now I’m living in Mexico. Recipes are in cups, teaspoons, and tablespoons. Both centigrade and imperial temperatures are used. My oven defaults to Fahrenheit. The pizza ovens are all in Fahrenheit. All of the building materials and tools are in Imperial units – plumbing, lumber, wrenches, etc. I asked a building maintenance guy to help me install a battery disconnect. Although I knew it was 13 mm bolt, he told me I needed 1/2"!!!
Yeah, one can claim to be metric, but as long as everyone gets along, it doesn’t really matter.
The above is true, but here is an interesting little fact: You know those temporary yellow signs you see on roads warning you in advance of roadworks? The ones that count down 800yds, 600yds etc… They are actually set at 800 metres, then 600 metres etc, not yards at all.
The reason for this is that the guys who set the signs out use the white lane-marking lines to measure the distance… 11 white lines + spaces = 99 metres. The tolerance is 10%, and as the yards/metres conversion falls within that, they just use metres.
Cite: Chapter 8 of the TSRGD (PDF warning - see diagram on page 241). I learnt this while attending a Temporary Traffic Management Workshop run by the Highways Agency recently.
Amazed to see other countries that have the Imperial/metric mix, I thoguht it was just Canada that was that way (due to our dual nature of being a former British (metric) colony, while being closely tied to the US (Imperial)). Yup, things official are in metric, as are road signs and speed limits (which could be argued as “official”) and tempuratures (as in the weather), but imperial in colloquial measurements like personal height/weight, as well as cooking ovens (like cars, our ovens have both C and F on them, and from boxes of food I buy in the store, I noticed the cooking directions either give the required tempurature in just F or F with the C in brackets (exact or rounded))
So, since this is GQ, I’d like to ask, are there any countries out there (maybe some foreign Dopers can speak from experience) where everything is either completely Imperial or completely metric and the other is very foreign?
I always find it odd that people from other countries think of (or expect) Britain to be a metric country. I’m only 32 and I don’t think of Britain as being metric. Yes food etc is labelled in grams and litres, but everyone thinks of their weight in stone and pounds, their height in feet and inches, and distances in miles.
Yes, I measure in centimetres if I’m doing DIY and need to buy supplies, as that’s how everything is sold. But I don’t think of that as the actual length, if you see what I mean. 
I must say that the notion of Britain being metric puts a big smile on my face. Wherever have people got that idea from?
In Sweden, that contrary to Britain really is metric, there are a couple of imperial enclaves. Bars, e.g., often serve beer in pint glasses, although often not per pint, but it’s a good try anyway.
Most of the rest of the world is completely metric, mainland Europe definitely is.
The only exceptions coming to my mind are screen sizes, which are given in inches, and aviaton / nautic stuff, which is in nautical miles, feet etc worldwide with the exception of Russia and the European gliding community.
As far I as know there is no Swedish pre metric equivalent of the pint, so I would assume that that practice is something we have imported(including the glasses!) from the British.
When Britain started colonising Canada, I’m pretty damned certain they used Imperial measurements. In fact, the British Empire created it. Metric has it’s origins in France, I believe. I’m not sure why there’s such a strong connotation between Britain and metric. Where does that come from?
When I first launched my beer drinking career the standard measure was 50 cl. Over the years the glasses have shrunk down to 40 cl with no room for a head. Then all sorts of Irish and British pubs popped up and brought the pint glass with them, with or without a marking stating 50 cls up to here (instead of filling it up, bastards!).
Close, but you still got exceptions. 
Keeping Up Appearances is a very old show too.
My sister’s new car has the speedometer in KPH only, any other car I had seen previously in the Republic of Ireland had both MPH and KPH. As stated above speed limits in the Republic are all in KPH but if (and my sister does this a couple of times a month) you visit Northern Ireland you have speed limits in MPH but your speedometer in KPH.
That’s irrelevant as all our road signs are still in miles.
I’ve never been to the UK but I often listen to BBC Five Live on my internet radio. I hear lots of callers which are usually just ordinary people but I don’t recall ever hearing a caller “naturally” use a metric unit in except perhaps degrees C. This leads me to think that the UK is metric more for political correctness and official stuff than “normal” real life.
Lengths are in feet and inches. Body weight in stone. Land area in acres.
A medical person was on once talking about babies’ weights in Kg and the host kept asking “how many pounds is that?”.
In New Zealand, even my 85 year old dad now tends to talk metric.
I have friends in NZ and they use metric, the only thing they never give in metric is weight. I have never heard any Kiwi refer to anything but “stone” to indicate their body weight. Of course that’s just people I know and they are all from Christchurch so it could be local
That’s surprising because I think the use of stone is pretty rare in NZ these days. I’ve been away for ten years and I stopped thinking of my weight in stone many years before that. I don’t think I’m all that unusual.
Yeah, I was startled when I saw the UK road signs in miles. I thought they’d gone all metric for road signs, like Canada did.
Obligatory and usual nitpick: the US System of Customary Units is not the Imperial System. The volume units differ: 1 Imperial gallon (4.5 litres) is not 1 US gallon (3.8 litres). Also, the Imperial pint has 20 fluid ounces, while the US pint has 16, so the Imperial fluid ounce is smaller than the US fluid ounce. Comparison between the US and Imperial systems
This becomes important when discussing gas mileage on the US/Canada border. L/100 km, miles per US gallon, or miles per Imperial gallon?