LONDON -- Big Ben has been striking the hour for 156 years, but lately it's been slipping. It was out a whole six seconds last summer.
The guys who maintain it, like Ian Westworth, have been struggling to keep it on time -- even using pennies as weights.
"By putting on or taking off a penny on the pendulum, you speed up or slow down the clock by two-fifths of a second in 24 hours," Westworth said.
Now Big Ben is on borrowed time, so worn out it may have to be stopped and completely overhauled before the 14-foot long, 600 pound minute hands fall off.
Newspaper columnist Quentin Letts believes stopping Ben Ben would be like stopping the heartbeat of London.
"This is the marrow in our bones, this old clock," said Letts. "The thought of it not being there, or one hand flying off, or heaven forbid the thing going digital, is just too gruesome to consider."
It would be like losing yet another old symbol of London when others seem to be dropping like flies.
The iconic hop-on hop-off buses are gone, replaced by unloved models. The old red phone boxes are only kept around for the tourists since the advent of the cell phone. And London's famous black cabs are now threatened by Uber.
If Big Ben were to go, "it would be a calamity. A catastrophe, a disaster," Letts said. "And for that reason I suspect they will find a way round this."
But it seems they are running out of time -- literally.