Passengers are demanding to know why it is going to take more than six months to fix and upgrade escalators at Highgate Tube station.

In the time that it will take Transport for London (TfL) to carry out the maintenance work, 381,000 babies will be born in the UK and the moon will travel 10million miles around the earth.

In China, a construction company once managed to build a 15-storey hotel in six days. But TfL still insists the essential repair work to the Highgate station escalators cannot be carried out in less than half a year.

The work involves replacing every part of each of the three escalators, from gear box to each individual step, and the escalators at the station in Archway Road will be upgraded one at a time.

Regular users say six months to carry out the work is too long.

Cyril Sheridan, of Stanhope Road, Highgate, and his wife have stopped using the station. “I am 91 and my wife is three years younger than me,” said Mr Sheridan. “Getting down those steps is a misery. We can’t cope. What is TfL doing? Why is it taking so long? We are entitled to a full explanation.”

Tina Janering, who works at Highgate School, said: “I think it is appalling. I wrote a letter asking why is it taking so long. It must be one of the deepest stations in London. I see people struggling with cases and buggies. They have shown no sense of urgency.”

Millions of passengers will ride the Northern Line during the six months before the escalators are fixed.

But TfL is advising customers who are unable to manage the long staircase down to platform level at Highgate to hop on a bus and travel to Archway, East Finchley or Finchley Central Tube stations.

Nigel Holness, operations director for London Underground, said: “Tube escalators are huge complex machines used by thousands of passengers a day. Two escalators run from the ticket hall to platforms and while these are being worked on there will always be one in operation in the up direction.

“This means there will be no down escalator to the platforms until June 2013. We are sorry for disruption caused by this crucial work.”