Parliament's clocksmiths have admitted that the chimes of Big Ben have been delayed by up to six seconds over the past two weeks. This has been a problem for BBC Radio 4's PM programme, as it broadcasts the chimes live and has thus had to deal with short periods of on-air silence.
Big Ben
Clocksmith Ian Westworth described the 156-year-old clock as "temperamental", and told BBC News that "it does have a little fit every now and then".
Mechanics discovered the delay, which may have been caused by changes in temperature and air pressure, over the weekend of 15 and 16 August, and have gradually corrected the problem. Big Ben is adjusted by adding or removing old coins from the pendulum to alter the rate at which it swings.
The clock is now accurate to less than one second, according to a spokesman from parliament, and routine checks are being conducted every day (rather than three times a week) to keep it that way.