The government is to press ahead with a £27bn programme of roadbuilding over the next five years, the chancellor has confirmed, with a wider infrastructure strategy to be unveiled at a later date. Rishi Sunak billed the move as “the largest ever investment in English strategic roads”, and pledged additional funding of £500m a year to top up a pothole fund.

The road investment strategy will see all vehicle excise duty hypothecated for roads. The policy was first announced by George Osborne in 2015 and the sum pledged on Wednesday was about £2.1bn higher than the funds earmarked by the Treasury last autumn.

Sunak said the £27.4bn from 2020-25 would “pay for work on over 20 connections to ports and airports, over 100 junctions, 4,000 miles of road”.

Among the schemes he promised to deliver was the controversial work to expand the A303 at Stonehenge, described as catastrophic by environmentalists and archaeologists. Sunak said it was “one of those totemic projects symbolising delay and obstruction”.

He added: “Governments have been trying to fix it since the 1980s. Every year, millions of cars crawl along it in traffic, ruining the backdrop to one of our most important historic landmarks. The A303 – this government’s going to get it done.”

Other road development schemes that he pledged would go ahead include the Lower Thames Crossing between Kent and Essex, the A46 Newark bypass in the Midlands, and the Pant-Llanymynech bypass along the Welsh border route of the A483, as well as work on “unclogging Manchester’s arteries”.

The transport secretary, Grant Shapps, said the first priority in the updated road strategy would be to fix the existing strategic roads rather than build new ones. He said: “Only where existing roads are simply not up to the job the country asks of them are we asking Highways England to develop wider, realigned or, in a few cases, wholly new roads to keep people and goods moving.”

The additional £500m a year to fill potholes will come on top of around £1bn already pledged for annual repairs, according to the Treasury. Sunak said the funding would fill 50 million potholes.

Darren Shirley, chief executive of Campaign for Better Transport, said the money was “welcome [but] long overdue”. But motoring groups queried whether it would be enough, with evident decline after an annual spend of £5bn on Britain’s local roads during the past decade. Steve Gooding, director of the RAC Foundation, said that while potholes were the “poster child” for maintenance, road bridges also needed billions for repair. “The evidence of motorists’ eyes is that the already poor state of the roads has worsened significantly following the recent flooding and storms.”

Others warned that the roadbuilding was incompatible with climate commitments. Prof Greg Marsden, of the Institute for Transport Studies at the University of Leeds, said there should be a moratorium on new road construction pending the take-up of electric vehicles, adding: “The focus on shovel-ready infrastructure expansion on the roads will, regrettably, simply dig us a bigger climate hole to get out of.”

Sunak said that roadbuilding would be part of a broader national infrastructure strategy, the publication of which has now been delayed until later this year. He said that would involve capital investment of more than £600bn over the parliament. According to the Treasury, that includes spending on rail, communications, schools, hospitals and power networks.

Money announced in the budget to improve communications infrastructure includes £5bn for gigabit-speed broadband in rural areas of the UK, and £510m of new investment in the shared rural mobile phone network. Sunak said this meant 4G coverage would reach 95% of the country by 2025.

Another £1bn was allocated from an existing Transforming Cities fund to improve bus and cycling infrastructure in 12 cities, including Stoke, Preston, Derby, Nottingham and Southampton. Sunak also said West Yorkshire would share in £4.2bn in funding settlements for eight mayoral combined authorities, allowing them to help create London-style integrated transport. Shirley said the money would “allow these areas to develop transport solutions that work for local communities and provide affordable, sustainable public transport for millions of people”.

Sunak disappointed northern transport leaders by reaffirming support for a Manchester-Leeds rail link and HS2, but not offering any more firm funding towards the Northern Powerhouse vision, although another £20m was given to develop plans for a proposed Midlands rail hub.

The chancellor also indicated that the Treasury would review its Green Book rules, calculating the cost and benefit of infrastructure investment, which have been criticised for making schemes appear less beneficial outside the south.