At Euston fire station drivers in lorries, cars and taxis sounded their horns in support of the firefighters. The union's own fire engine was driven onto the station forecourt, with Johnny Cash's Ring of Fire song blaring from a loudspeaker:
We have been receiving a lot of public support today at picket lines across London.
There is solid support for the strike - but it is a sad day in some respects because firefighters don't want to be on strike.
More top news
Bees Number One is 'best in the league."
A union has said it is worried plans for Wandsworth and Richmond councils to merge may lead to job losses.
A computer disk contained a secret file on the fatal shooting of Mark Duggan by police has been lost.