The vandals removed and defaced many of the signs and mounted pressure on Islington council to replace them with imperial-only signs. This has left the borough with a series of width restriction signs that are labelled as 6'6" , when in fact they mean 2.0 metres. (In most other places these are dual-unit signs) Considering that vehicle dimensions are specified in millimetres in manuals, anyone without a calculator is at risk of doing damage to their vehicle.
I managed to find one sign (see below) that escaped the ravages of the BMWA. However, this sign is not without its flaws.
The sign states Humps for 600 mtrs.
According to the BIPM, there should never be any abbreviation for the metre – or any metric unit for that matter. Only the whole word or the SI symbol (m) should be used.
Therefore, the sign should read: Humps for 600 m
Nonetheless, it's always a pleasure to see metric signs on our roads and this is evidence that they pose no danger to road users, who generally speak in metres anyway.