Shortest section of 30mph in the UK? - Mapmaker
There is a section of road near to where I live where a 20mph zone ends and a 30 begins. After the 30, it returns to a 20 zone.

All very well... except the 30mph section is three feet long.

On an adjacent road, the 30mph section is ten feet long.

Well done Southwark.
Shortest section of NSL in the UK - henry k
There is a section of road near to where I live where a 30mph zone ends and the NSL begins. After the NSL, it returns to a 30 zone.

All very well... except the NSL section is about 30 feet long.

Well done Elmbridge / Surrey.

We also have a 20mph zone on thw A308 at Hampton this is a significant feeder to J1 of the M3,
Kempton Park Race course etc and Heathrow.
I have yet to see anyone travelling on it at 20mph outside the rush hour.

Shortest section of NSL in the UK - Cliff Pope
It reminds me of two signs in our local swimming pool. One says "No buoyancy aids beyond this point" and next to it another says "No non-swimmers beyond this point". So there is a one-foot wide strip where non-swimmers are obliged to flounder unaided, having discarded their armbands.
Shortest section of NSL in the UK - Armitage Shanks {p}
Village near me has a "Please Drive Carefully" but no speed limit so 60 would legal but stupid! Turning off the NSL road is a 20 yard cul de sac with a 30 sign at the beginning of it!
Shortest section of NSL in the UK - andymc {P}
Andy ! - in the style of Peter Kay "Howwww dare youuu" and sniipped - PU Mod.
andymc
Vroom, vroom - mmm, doughnuts ...