It usually takes a few days to unpick the ins and outs of a government Budget. At first sight, today’s budget doesn’t seem too bad for motorists, particularly as fuel duty has been frozen again.

Perhaps the hidden highlight is that government is also promising a major ‘Road Investment Strategy’ by the end of the parliament.

Although we’ll have to wait four years – mainly because the UK should have balanced its books by then – some proper road improvements - and even whole new roads - will be desperately needed by the end of the decade.

Trouble is, building new roads has been seen as political dynamite since 1990. The tipping point was probably the Conservative government’s ‘Roads for Prosperity’ white paper of 1989.

It was billed as the ‘largest road-building programme in the UK since the Romans’ and proved to be something of a turning point in the UK’s rather odd relationship with the private motor car.

Huge protests broke out about plans to build the M3 extension beyond Winchester and the M11 extension/East Cross Route through east London.

Although the two roads – both commercially important – were built, the ferocity of the protests put a stop to major road building in the UK, leaving us with a comparatively tiny motorway network compared even to counties such as the Netherlands.

The picture at the top of this column shows one of those abandoned early 1990s motorway projects. The building is the Earls Court 2 exhibition centre in West London, which is currently being demolished.

The small tunnel that’s visible under the building was a space left for the planned Western Environmental Improvement Road (WEIR), which would have run north-south through west London, relieving the huge weight of traffic around Earl’s Court and over the local bridges.

WEIR died a death thanks to a combination of the early 1990s recession and massive battle over the M11 extension, which made a celebrity of the professional anti-roads protester ‘Swampy’.

Ironically the whole road-building programme is said to have been finally sunk in the last budget delivered by a Conservative government, back in 1996.

So, has the first Conservative budget since then, nearly 20 years on, indicated that the UK is finally getting back to building roads?

Well, it might, thanks to the budget's other big announcement concerning motorists: the changes to vehicle excise duty (VED).

The new VED (commonly called 'road tax) system for 2017 does look a bit like a double-edge sword.

The plans see Chancellor George Osborne undoing a major policy shift triggered by Winston Churchill when he was Chancellor of the Exchequer in the mid-1920s.

Road tax was established in 1906 to pay for road building as car and commercial vehicle ownership took off.

Unusually for a tax, the money raised was ring-fenced and directly allocated to road spending, something criticised by Churchill. That was finally brought to an end in 1937.

From 2017, however, all the money raised by English VED will be put into a fund for an English Strategic Road network. That’s the good news.

The bad news for the Treasury is that basing VED on CO2 output was about to result in a serious shortfall in funds as drivers switched to more economical cars.

According to the budget presentation, VED income would have fallen from around £4.4 billion today to under £3bn by 2020-21.

The new VED formula will keep the income at around £4.3bn, but will be achieved by a new ‘first-year rate’ based on CO2 output.

Buy a car emitting over 255g/km and you’ll pay a massive £2000 VED on registration.

And if that car had a list price of over £40,000, the VED costs will be £440 for the next five years. In year six, though, it will drop back to £140.

Perhaps the only upside is that the money English drivers pay on VED will, for the first time since 1936, go directly into road maintenance and building. If indeed it is possible to build any new roads at all in crowded England.