The new Routemaster bus finally hit the road on Monday – but its iconic open back had to be kept shut after a malfunction on the maiden voyage.

The first paying passengers were unable to hop on and off after a problem with the back door meant it could not be left open.

Engineers had to be called in to repair the �1.4million bus, causing delays on its first day of service on one of the busiest routes in Islington, the number 38.

David Hampson-Ghani, of Transport for London (TfL), said: “There was a problem with a switch. I think it just lost a signal. It just meant the back door was closed like a normal door while the bus was moving.”

The launch had been put back a week because the vehicle’s paperwork was not completed in time, but despite the teething problems, TfL officials were pleased with its reception.

Mr Hampson-Ghani said: “The reaction of the public has been fantastic. It was like we were the Pied Piper – there were just scores of people following us. It was like the Beatles had come to town. But it’s just a bus!”

The 38 travels along Balls Pond Road, Essex Road, Upper Street and Rosebery Avenue on its journey from Hackney to Victoria. There will be a fleet of eight Routemasters by the end of May, costing �11.4million in all.

The Gazette jumped on board on Monday, jostling for space with hordes of bus fans and media from as far afield as Brazil.

As we pulled out of the garage, countless passers-by stopped in their tracks to film it on their mobile phones.

The new design looks very modern and – apart from the open back – bears little resemblance to the old Routemaster which was withdrawn from all but two “heritage routes” in 2005.

The maroon and gold interior and double staircases help set it apart from standard double-deckers.

Most passengers were impressed, including student Cansu Caran, 20, of Albion Road, Stoke Newington, who said: “It looks very old school – but new at the same time. It’s really nice and it’s great to be able to jump on and off.”

But one or two were not so keen. Griff Owen, 58, a musician and bus enthusiast from Palmers Green, said: “I think it’s an indulgent waste of money. I think Boris just wanted to make his mark.”