Diesel drivers will receive compensation to encourage them to scrap or "retrofit" highly polluting vehicles under Conservative plans to reduce emissions to be unveiled later this week.

The Government will on Friday publish its new air quality strategy which will include plans for a "targeted" diesel scrappage scheme, The Telegraph has learned.

Ministers will also consult on plans to give people help with retrofitting older, more polluting diesel vehicles to reduce the levels of harmful nitrogen dioxide that they emit.

The Conservatives will warn local authorities against imposing pollution taxes on motorists amid concerns that doing so would "punish" motorists and become an election issue.

It comes after Theresa May, the Prime Minister, said last month that she was "very conscious" that motorists were encouraged to buy diesel cars under Labour more than a decade ago because of concerns about carbon emissions.

A Conservative source said: "We will help drivers on modest incomes who bought their diesel vehicles in good faith, having been badly advised by the last Labour Government. We are cleaning up Labour's mess."