Oxford Circus Tube station was temporarily shut today because it did not have enough staff.
Travellers who wanted to use London Underground found the station was for almost an hour.
A Transport for London spokesman said: "Due to a staff shortage, Oxford Circus Underground Station was closed for a short period between 8.58am and 9.46am with trains not stopping at the station. This has now been resolved and all trains are stopping normally.
"During the short station closures, customers could continue to use Tube stations in the area, including Bond Street, Piccadilly Circus and Tottenham Court Road."
Passengers were evacuated from the station as an emergency alarm sounded.
A repeated announcement said: "Ladies and gentlemen, your attention please: due to a reported emergency would all passengers leave the station immediately."
A sign reading "Emergency do not enter" was illuminated over the entrances to the station before the gates were closed.
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