A million households were left without power, rail services were in chaos and shops and schools forced to close after a massive power cut in Noord-Holland province on Friday.

The failure itself lasted about an hour but the knock-on effect disrupted public transport services and forced hospitals to use emergency generators.

Train services in much of the country will remain disrupted for the rest of the day because of the massive power failure, officials said on Friday afternoon.

Engineers had to free hundreds of people who were trapped in trains when the power went off. Amsterdam’s central station is packed with trains which cannot leave and thousands of travellers have been stranded.

Airline KLM cancelled some 20 flights because planes could not land but officials say the airport is now returning to normal. There was also a jam of ships waiting to use the sluice at Ijmuiden which could not be opened.

Police

The power cut hit large parts of Amsterdam, Haarlem and other Noord-Holland towns and villages. According to local broadcaster AT5, there were no serious incidents due to the power cut.

People were trapped in lifts and trams, shops were forced to close because their automatic doors and tills no longer worked, and schools sent thousands of pupils home. Extra police were drafted onto the streets to control traffic.

The power failure was caused by problems at a sub-station in Diemen and grid association Netbeheer Nederland said the outage is one of the most serious in the last 10 years.

The cause of the power failure has not yet been established. A spokesman for grid operator Tennet said it is not clear why the back-up system which should have kicked in did not function properly.