Mums driving their kids to school in giant fuel-guzzling 4x4s are set to be hit hard this week when Gordon Brown announces his Budget reforms.
The Chancellor is set to reveal plans to create a new 'superband' of car tax that will see vehicles pumping out more than 225g of carbon per kilometre charged nearly £200 each year.
The news will be most unwelcome to the hordes of mothers who cruise the busy streets in highly impractical so-called Chelsea tractors; the 4x4s more suited to the Welsh valleys than the narrow roads and tight turns of SW3.
Vehicles such as the Jeep Cherokee, Land Rover Discovery and Porsche Cayenne already cost a small fortune to buy and can be several thousand to cover with motor insurance, and now even more money is going to have to be forked out for road tax.
It's not all bad news, however, and Gordon Brown is due to announce that cars at the other end of the scale - smaller, more environmentally friendly vehicles - are to receive a deduction in their car tax.
A spokesperson for CoverGirl Car Insurance Services, specialists in Car Insurance for Women, said, "If you find yourself affected by the Budget and are going to have to pay more road tax, no doubt you'll be looking to make savings elsewhere.
"Browsing the net for cheap car insurance could help and you're bound to save money by buying a policy from a dedicated car insurance for women provider."