Metric signs on UK roads

It is a common misconception that metric signs are not permitted on or near roads in the UK. In reality, the law permits and sometimes requires metric, imperial or a mixture of metric and imperial measurements. 

On this page, we show examples of authorised signs showing metric measurements and also illustrate the sometimes confusing results of mixing two systems of measurement.
 
The illustrations are in two sections:
 
Section A. Road traffic signs authorised by the Traffic Signs Regulations and General Directions (TSRGD). 
 
Section B. Signs authorised by other legislation, in particular that relating to town and country planning and health and safety.
 
 
 
Section A. Road traffic signs authorised by the Traffic Signs Regulations and General Directions 
 
Motorway driver location posts were among the first metric signs introduced on UK roads:
 
Marker post
 
In 2003, driver location signs were introduced experimentally on motorways and are now appearing on other primary routes. The number at the bottom of this sign is the distance in kilometres from the start of the motorway:
 
Motorway location marker
 
New vehicle length restrictions must be signed in metric alongside imperial (standalone imperial vehicle length signs can remain in place until they are replaced):
 

Length restriction

The depth of a ford must be indicated in metres:

Ford sign
 
In 2011, the internationally recognised symbol "t" for tonne or tonnes became obligatory on new weight restriction signs:
 
Weak bridge sign
 
The signing of height and width restrictions in metric has been shown to be cost effective and became mandatory (alongside imperial) in 2016:
Metric width restriction sign dual width and height signs Bridge sign
Dual triangular warning sign Metric height warning signDual bridge headroom sign

Adding all this together:

 
Rotherhyte multiple sign
 
 
Section B. Signs authorised by other legislation, in particular that relating to town and country planning and health and safety
 
In practice many authorities can grant themselves 'deemed' or 'express' planning consent. See our page on the legal position, www.ukma.org.uk/road-signage/detailed-legal-analysis, for further information.
 
Footpaths may be signed in metric for the convenience of walkers, so long as planning permission is received:
 Foot path sign
 
Other distances may also be signed in metric, but again planning permission is always required:
Metric distance sign to car park
Metric pedestrian crossing sign
 
Metric finger post sign


                

 
 
 
Tramway speed limit signs are for the benefit of tram drivers:
 Tramway speed limit sign 
Electric cables overhead may affect safety and therefore require metric signs:
 
Forest commission overhead cable warning sign    
 
This sign warning of problems some way ahead would have required planning permission:
 
Advanced warning of weight limit
 
Where clearances are shown for reasons of health and safety, metric units must be used:
Height limit on entrance to car park sign Canopy height sign
 While we are on the garage forecourt, we are reminded that fuelling is metric too.
 
And, as has often been said, you can put up any sign you like using any measurements you like, so long as it is authorised under the Town and Country Planning Acts:
 
Seafront information sign
 
     Health club sign                                    Private bar sign