Hundreds of licences granted for new oil and gas projects in the North Sea under the Conservatives have so far produced only 36 days’ worth of gas, according to analysis.

Research by the energy consultancy Voar and the campaign group Uplift found that between 2010 and 2024, the government handed out hundreds of new North Sea oil and gas licences in seven licensing rounds.

This led to 20 new and relicensed fields that have the potential, over their lifetime, to produce enough gas to supply the UK for only six months. To date they have produced the equivalent of 36 days of extra gas.

The findings cast doubt on claims by Reform UK and the Conservatives that new drilling licences in the North Sea would help to reduce energy bills and boost the UK’s energy security.

Tessa Khan, the executive director of Uplift, said rightwing politicians and the oil and gas industry were trying to mislead the public. “Some politicians are trying to sell us a dangerous fantasy of endless gas reserves, when the truth is – after 50 years of drilling – we have already burned most of it,” Khan said.

“A month’s worth of gas from 14 years of licensing by the last government shows the complete folly of pursuing this policy. It’s barely enough gas to last from now until May Day.”

A rise in energy prices caused by the US-Israeli war in Iran has intensified the debate over how to ensure the UK has a reliable supply of affordable energy.

Labour’s decision to ban new oil and gas licensing and focus instead on homegrown renewable energy has been welcomed by many economists and climate experts. However, it has come under repeated attack from Kemi Badenoch and Nigel Farage in recent weeks.

The Reform leader called on the prime minister to “open up the licences, and become self-sufficient in natural gas”.

Badenoch claimed: “Drilling in the North Sea and expanding other sources of generation … is the only way we can protect families from rising bills.”

However, experts say the North Sea is a “mature basin” whose output has declined by 75% since its peak. They say 90% of its reserves have gone.

New licences would have no impact on bills because the price is set by the international markets. Official data shows new licences would have a minimal impact on the UK’s dependency on imported gas.

Instead, campaigners say a more effective way to achieve energy security for Britain would be to double down on renewable energy and implement a mass programme of home improvements, from better insulation to installing heat pumps.

Khan said: “New drilling would not take a penny off our bills, something even the industry has conceded. The only way to insulate ourselves from oil shocks is to double down on renewables and upgrade homes, so we can free ourselves from fossil fuels. This is just common sense in today’s world.”

Jess Ralston, the head of energy at the Energy and Climate Intelligence Unit, said issuing more licences would be a “sticking plaster” that would not help British consumers.

“The reality is that we’ve drained dry around 90% of oil and gas there,” Ralston said. “To stop the UK being so vulnerable to energy crises, often sparked by war, lowering fossil fuel demand through electric vehicles, heat pumps and renewables remains the most credible long-term solution.”

The Conservatives have been contacted for comment.