The impending sale of the M6 toll road and rise in ultra-low emission vehicles (ULEVs) has reignited the debate over alternative taxation models and whether pay-as-you go road pricing has a future in the UK.

The Government says it has no plans to introduce road pricing, but falling fuel duty has led some to suggest it is only a matter of time before alternative revenue streams are sought to plug the shortfall.

Steve Gooding, director of the RAC Foundation, said: “I think road pricing is a fabulous economic theory that is extraordinarily hard to make work in practice.

“If it could be made to work I suspect somebody somewhere in the world would have done it by now and nobody has.” 

However, Gooding told delegates at the Westminster Energy, Environment and Transport Forum that the “growth in traffic is going to continue to put strain on the network and it’s probably something we can’t just build our way out of”.

He also acknowledged that changes in the vehicle parc, with more ULEVs being adopted, meant that traditional motoring taxes will have to be revisited. As a result, he predicts that road pricing could be introduced in 20 years.

Baroness Kramer, a former transport minister in the coalition Government, also believes the shift to ULEVs will make fuel taxation an irrelevance and force the Government to find another way to cover the shortfall.

However, she said: “The problem is when you have a system the losers all scream and the winners take the benefit for granted, so it’s very difficult to make such a fundamental change.”

The M6 toll, which went up for sale in February, is currently the only stretch of the road network where company car and van drivers are required to pay a toll apart from bridges and tunnels such as the Severn Bridge and Dartford crossing.

It starts at junction 3a, running through the north east of the West Midlands before rejoining the M6 at junction 11a, and opened in December, 2003, at a cost of £900 million.

Usage has been an issue. An estimated 200,000 vehicles pass through the ‘spaghetti junction’ on the M6 every day, while the M6 toll road section only serves about 50,000.

It was originally forecast that the 27-mile stretch of motorway would cater for 72,000 vehicles a day.

Charges vary, based on the type of vehicle and the day of the week, but can be up to £5.50 for a car, £10 for car and trailer, and £11 for an HGV, van or coach.

The problems facing the toll road, operated by Midland Expressway, a subsidiary of Macquarie, have been compounded by its debt.

It is 100% owned by a group of 27 banks and hedge funds, with a total debt of some £1.9bn, following a debt restructuring in December 2013. Any sale is expected to generate enough money to fully recover that debt.

In recent years, traffic numbers using the toll have at least increased, with 17.4m vehicles using the road in 2015 – a 12.5% increase on the previous year.

Reported losses were also down from £32.5m in 2013 to £28.6m in 2014.

Councillor Darren Cooper, leader of Sandwell Metropolitan Borough Council, a member of the West Midlands Combined Authority (WMCA), has written to the transport secretary Patrick McLoughlin suggesting a partnership to take over the M6 toll road.

He is frustrated that when there is an accident on the M6 it grinds to a halt, yet the toll road can be virtually empty.

Cooper says reducing the tolls to zero during an emergency, such as a major incident on the M6, could provide a solution. McLoughlin has said he will look at the suggestion.

“At the very least we have to get arrangements in place so that the M6 toll can be opened up for free use when there is a serious incident on the M6 or M5,” said Cooper.

As part of its devolution plans, the WMCA had previously suggested making the road free for HGVs, at an estimated annual cost of £15m, but no agreement from the Government was forthcoming.