Delays on the London Underground because of overcrowding have reached a five-year high, according to new figures.
The delays have reached a "very worrying" level on the Central, Victoria, Northern and Jubilee lines, according to the Liberal Democrats.
Figures obtained by the party's transport spokesperson on the London Assembly, Caroline Pidgeon, showed there were more Tube delays in the 2014/15 financial year than for five years.
She said: "The Mayor and Transport for London are constantly boasting about the record performance of the London Underground. However, there is an increasing problem of serious overcrowding for passengers on much of the Tube, and this is only going to get worse.
"These figures were dragged out of the Mayor and reveal that we cannot afford a day of complacency in tackling Tube delays and ensuring the Tube upgrades are funded.
"Improvements to the Tube are barely keeping up with the rising demand for travel created by London's booming population and record numbers of tourists."
The figures showed there were 237 delays in 2014/15 because of overcrowding, compared with 153 in 2010.