Visions of a monorail, trams or trains running between St Giles and Witney were among the ideas floated at the launch of Connecting Oxfordshire, by county council leader Ian Hudspeth in the spring.

With the need to address the issue of the heavily-congested A40 now urgent, and with the Government committing itself to putting money into improvements, the focus seems to have moved quickly from visions to practical solutions.

It is now reasonably certain that the solution will come down to buses — and some sort of scheme to provide a faster bus services offering arrival time certainty. Clearly, £40m will not buy a monorail system, but it should go a long way towards separating buses from other traffic.

A guided bus scheme would certainly achieve that, while having the advantage of being both fast and requiring only a narrow lane. Some readers will recall the level of support given to a Guided Transport Express scheme linking Oxford rail station with the Redbridge and Pear Tree park-and-ride sites.

That scheme was abandoned back in 2004, but only after some £800,000 of taxpayers money had been pumped into the scheme, first mooted in the mid-1990s. Oxford residents, understandably, had been concerned about the environmental impact.

But were guided buses to run beside the A40, that issue would surely not arise. Supporters of the idea can point to the guided buses running between Cambridge and Huntingdon, which the operator Stagecoach tells us has proved a great success since 2011, persuading many to leave their cars at home. It is indeed easy to imagine the image on our front page today being close to the Pear Tree interchange, rather than Cambridge. But the Cambridge scheme brings a warning too.

The time it took to complete, as costs far exceeded estimates, was to lead to legal battles, claims of fiasco and calls for a Government inquiry.

Remarkably, the Government has come up with the money without any firm decision having been made about what form the A40 improvements should take — with various ways of prioritising buses being looked at — while Mr Hudspeth, for one, is still not completely ruling out rail and monorail.

While the scheme planned for the A40 forms only part of the bigger Oxford Science Transit Plan — linking the city with various surrounding centres of research — it is an important part, and not just for scientists.

And it would be very unwise to keep the Government waiting for a bus solution, whether it is tidal or guided.