2040 was previously the target for the ban.
The British Prime Minister is bringing forward plans to ban the sale of new petrol and diesel cars, to 2035.
He'll announce it officially later, as he launches UN climate talks in the UK.
The policy change was made following concerns from climate change experts that the mandatory transition to electric and hydrogen vehicles by 2040 would come too late to keep the UK on track to hit its net-zero carbon emissions goal by 2050.
Boris Johnson will discuss the new policy at an event in London later, which preludes the UN COP26 climate summit which will be hosted in Glasgow in November.
