What an extraordinary morning. Almost exactly four years to the day since I pitched up at Boris Johnson’s campaign headquarters with detailed plans for a futuristic, electrically-driven Routemaster, the real thing drove silently on to Trafalgar Square in central London.

Although the ‘New Bus for London’ sticks to Autocar’s mechanical recipe, Northern Ireland’s Wrightbus operation moved the concept on by creating a quick-loading double decker with three doors and two staircases. Design consultancy Heatherwick Studio then came up with the exterior’s super-distinctive glazing and the finely-detailed interior.

Primarily, what makes this bus such a huge leap forward for public transport is the drivetrain and super-rigid aluminium spaceframe body. It’s a range-extender, using a 4.5-litre diesel generator to power and recharged the battery pack. The upshot is that it sails through heavy traffic smoothly (thanks to the electric motors and single-ratio ‘box) and, for much of the time, is running silently on battery power.

Even when the engine/generator kicks in, it is just humming over at 1300rpm. But God is in the details. For example, each passenger on the upper deck gets their own low-voltage downlighter for a calming, ambient, atmosphere.

Today’s double deckers have harsh strip lighting which, as somebody once said, makes bus travel like sitting inside a fridge. This morning, I watched the first NB4L floating up Whitehall and around Trafalgar Square, amazed at the serene contrast with the straining and droning conventional buses that were alongside it.

The bigger picture, however, is that the Mayor of London has not only managed to commission the first bespoke London bus for half a century, but it is also one of the most technically advanced and it is made in the United Kingdom.

Like the recent re-inventions of the Mini, Range Rover and Rolls Royce, this country has again shown that it can leap into the future, by adopting the best of the past. But the biggest impression left by my trip to Trafalgar Square this morning was the sheer goodwill generated by the new bus.

Passing members of the public tried to get onboard and tourists snapped manically. Just before it drove onto the square, with Boris Johnson standing on the open platform, a senior citizen squeezed through the stationary traffic to shake the Mayor’s hand. ‘Boris’ she said ‘thank you for bringing back the Routemaster.’