Excellent advice!

If you ignore it you will end up in the extra.  There are several major roadworks in Farringdon.  Each has its own diversion and each diversion ignores the existence of all the other diversions.  So if you follow one of them you find yourself in an infinite loop.  We know the roads round here intimately but we were on our third loop before we found a way to escape.

A light frost in central London and a thick mist rising from the Thames first thing.  I'm amazed the sun burnt through for a while.