A 'targeted' scrappage scheme to get older, more polluting vehicles off the roads could be introduced as part of efforts to tackle illegal air pollution, the government has said.

In plans published for consultation, the government said there could also be central funding for local measures ranging from redesigning roads to boosting infrastructure for walking, cycling and electric vehicles.

And there could be support for councils which wanted to retrofit vehicles to cut air pollution from local bus, taxi or HGV fleets.

Ministers were ordered to draw up the new clean air plans following a court challenge by environmental lawyers ClientEarth, with the High Court ruling that existing government proposals to meet EU-mandated pollution limits were not sufficient.

The Environment Department (Defra) lost a last-minute High Court bid to delay revealing the draft plans to reduce illegal levels of nitrogen dioxide, much of which comes from diesel vehicles, until after the general election.

Documents published by the Government suggest the most effective way of cutting nitrogen dioxide is thought to be implementing 'clean air zones' in 27 towns and cities where air pollution levels are illegally high.

Measures implemented in the zones could include charging motorists who drive the dirtiest vehicles, such as the 'ultra low emissions zone' that London Mayor Sadiq Khan is implementing in the capital.

The consultation said local authorities had powers to implement clean air zones, and that, where the evidence shows persistent illegal air quality, councils must develop plans to achieve compliance within the shortest time possible.

But the Tories said they were opposed to Labour's approach of 'hitting motorists in the pocket by imposing charging zones and increasing parking charges'.

Instead they proposed a series of measures including funding and regulatory changes to support uptake of electric and hydrogen vehicles and increasing electric car charging points.

Measures also include tackling road humps and poorly managed traffic lights that increase congestion and pollution, 'real driving emissions' tests for vehicles and better consumer advice when buying cars.

Environment Secretary Andrea Leadsom said: 'Improving air quality is a key priority as we support businesses in building a stronger and cleaner economy.

'Our plan today sets out how we will do just that - including presenting options for targeted diesel scrappage schemes.'