Sir Bernard Hogan-Howe says that drug-testing would help cut the number of users - as the risk of losing your job would act as a deterrent.
"It seems to me we have got to plant in people’s minds something to affect the demand as well as supply. You can think of many occupations where if you were working with a colleague you would want to be sure in fact that they were drug free."
More top news
Cressida Dick said that around £700m of savings have already been made.
Tourists have been left scratching their head after the surprise announcement of the closure of the world's largest museum of oddities.
Scores of RMT union members will vote in the coming weeks on whether to launch a campaign of action.