Kintish failed for the first time in 6 years

I was running a workshop in London at 2pm and left home in Manchester at 7.30am.The car journey takes 3 hours generally so I believed I had allowed enough time.
When we got stuck at Stoke (about 20% of the journey) and weren’t moving I took a deep breath and called my client to admit I was to let him down.
This has never happened in the 6 years I have been presenting.
He was very understanding and we have rearranged.
WHAT DID I LEARN?
Well, normally I travel by train so maybe it’s time to line Richard Branson’s, already deep, pockets yet further?