Britons warned of fuel price hike 'by end of the WEEK' after 'missed opportunity' by Rachel Reeves

He said: "The big worry for me at the moment, because we had a 20 per cent increase in oil prices in the last week, is that we will get something like a 5p to 10p increase at the pumps. I think that could come through by the end of the week."

The campaigner noted that recent inflation figures had fallen partly because petrol prices decreased, describing fuel costs as functioning "like a barometer" for the wider economy.

With 37 million motorists across the country, Mr Cox argued that supporting drivers should be a political priority.

Mr Cox was sharply critical of the Chancellor's approach to fuel duty, arguing that a major opportunity had been squandered.

He said: "She missed an opportunity here, a massive opportunity. All she had to do is say I'll cancel the fuel duty rise for another year, that's all she had to do."

The FairFuelUK founder expressed particular concern about unchecked profiteering within the fuel supply chain, describing those involved as "opportunistic profiteers".

He revealed he has been collaborating with Claire Coutinho on developing a scheme called pump watch to tackle the issue.

"This Government promised actually they would stop that, but I haven't seen anything yet," Mr Cox stated.

He identified two primary concerns: the planned 5p budget increase, which will be phased in over time, and the profiteering he believes will go unmonitored.

Mr Cox predicted that inflation would climb as a result of rising fuel costs, pointing to the acute sensitivity between pump prices and economic performance.

Oil prices have jumped approximately $15 in recent days to reach around $85 per barrel, he explained.

Should prices hit $100, motorists could see increases of 10p to 20p per litre, mirroring patterns witnessed during the Ukraine crisis and earlier oil shocks.

The impact on commercial vehicles would be particularly severe, Mr Cox noted, with a 44-tonne lorry achieving roughly seven miles per gallon facing an additional £100 per tank.

He dismissed the Government's repeated emphasis on economic growth, questioning where such expansion was materialising.

Mr Cox argued: "We're lagging behind everyone, and if she did put more money into people's pockets, they'd spend it - businesses would invest, and they'd employ more people."

Cox also launched a broadside against the Government's environmental ageda, dismissing net zero policies as an "Ed Miliband sort of Hans Christian Andersen fantasy of politics".

He called for the 2030 prohibition on new petrol and diesel vehicle sales to be abandoned entirely, warning that production lines would struggle to return to manufacturing fossil fuel vehicles.

The campaigner expressed concern that ordinary people would suffer as a result of these policies, criticising decisions to halt fracking and close oil operations.

"That needs to be scrapped because the actual benefits of that, the costs are five times more than any alleged benefits, and the costs are real, but the benefits are still in the air," Mr Cox concluded.