Since David Cameron became Prime Minister the average annual increase in the UK road network is just 7% of that achieved under his Conservative predecessor Sir John Major, Press Association analysis has revealed.
The total length of roads has risen by an average of only 180 miles per year with Mr Cameron in Number 10, compared to 2,650 miles when Sir John was in office from 1990 to 1997.
Analysis of Department for Transport (DfT) road length data shows that Mr Cameron has been outstripped by every PM except Gordon Brown since records began in 1951.
The six other Conservative PMs from Sir Anthony Eden onwards all oversaw an average increase of more than 1,000 miles.
Under Gordon Brown the road network actually shortened by 130 miles per year.
AA president Edmund King said that in the late 1950s and 1960s prime ministers of all parties understood it was "clear that more roads and particularly motorways were needed".
He blamed the slowdown since the mid-1990s on the advent of anti-road protesters such as Swampy, who fought to stop the widening of the A30 in Devon.
A five-year £15 billion road investment strategy for England was launched in 2015, but Mr King said a "fair portion" of this is being used for smart motorways, which involves utilising the hard shoulder to widen roads "on the cheap".
He added: "Improving transport infrastructure should be in the national interest rather than influenced by the political leanings of the prime minister at the time."
Steve Gooding, director of the RAC Foundation, said there is strong public and political reluctance to "concreting over the countryside" to build new roads.
"Arguably the most pressing challenge is keeping the tens of thousands of miles of the road network we already have adequately maintained," he said.
A DfT spokeswoman said "1,300 extra lane miles" are being created under the road investment strategy.
She went on: "We are providing the much needed capacity on the busiest motorways by either temporarily or permanently opening the hard shoulder to traffic. This can be done much more quickly than traditional road widening."
Bridget Fox from Campaign for Better Transport said focus should be placed on improving public transport and cutting road traffic.
She commented: "Rather than laying costly new roads, which simply generate more traffic and pollution, we're calling for better maintenance of existing roads and action to reduce the impact of the main road network on our health and the countryside.
"Reducing road traffic, with more attractive town centres and better public transport connections, is the most sustainable solution."
The DfT data includes all roads in the UK except minor private roads.
:: Here is the average yearly net increase in miles in the UK's road network under each prime minister since 1951:
1. John Major (1990-97): 2,650
2. Harold Macmillan (1957-63): 1,384
3. Alec Douglas-Home (1963-64): 1,288
4. Margaret Thatcher (1979-90): 1,133
5. Anthony Eden (1955-57): 1,028
6. Edward Heath (1970-74): 1,022
7. Harold Wilson (1974-76): 1,174
8. James Callaghan (1976-79): 1,063
9. Winston Churchill (1951-55): 815
10. Tony Blair (1997-2007): 434
11. David Cameron (2010-present): 180
12. Harold Wilson (1964-70): 107
13. Gordon Brown (2007-10): minus 130
NB: Harold Wilson's combined figure is 1,281