British Prime Minister Boris Johnson said on May 5 that he had spoken to the bosses of oil majors Shell and BP and underlined the need for investment in the country amid soaring energy prices.

"Our message to them, and what is very, very clear,...this is a moment where we need you as a country to invest massively in clean, green, renewables, in the stuff that is going to make a difference to people's energy prices," Johnson told reporters.

Calls for a 'windfall tax' have been growing as the two London-listed oil firms have reported billions of dollars in profits at a time when people are struggling with the rising cost of essential items from food to fuel.

Asked about a windfall tax, Johnson said: "What the country needs is a government that will take a big decision about how to fix our energy supply, and you don't do that simply by clobbering the companies that we need to make investments in our domestic energy security."