More than 100,000 London-bound rail commuters - a fifth of the overall total - have to stand at the busiest times of the morning rush-hour, according to Government figures.
Passengers on some morning and evening peak services are travelling on trains which are 60% over capacity on certain routes, the Department for Transport (DfT) figures showed.
More top news
New figures show that lifeboat crews in London were the busiest in Britain in 2014. We look back at some of their most dramatic rescues.
Vlogging from her home in London she has become a YouTube sensation, so successful she has just published her first book.
Health union workers were due to walk out on Thursday in a dispute over pay.