Whilst I was away over the bank holiday weekend, I noticed the engine emissions control system warning lamp stayed illuminated after starting the car one morning.
It stayed on for the whole journey of about 25 miles on mixed roads including motorways. The car drove fine and I noticed nothing untoward at all.
It stayed on again on the return journey. But when I started the car the next time it went out and stayed out as per normal.

It hasn't come back on again since over about 4 more journies including on a 2 hour plus motorway journey home today.

Is this something I should worry about? The car seems ok and is driving perfectly.