Britain’s dwindling energy reserves have received a major boost with the biggest onshore oil and gas discovery for more than 40 years.

Rathlin Energy last week announced that its giant prospect near the village of West Newton in East Yorkshire – 25 miles from York – could be ‘one of the largest onshore discoveries in the UK’.

It upgraded its potential reserves to up to 283million barrels of oil and 266billion cubic feet of gas.

Based on industry analysis, Rathlin could recover at least 59million barrels of oil and 160billion cubic feet of gas, worth a combined £840million.

It is the largest onshore discovery since British Gas struck oil at Wytch Farm near Bournemouth, Dorset, in 1973, when 570million barrels of oil were found. Wytch Farm, operated by Anglo-French giant Perenco, is Europe’s largest onshore oilfield.

Energy analyst Lucy King, of Wood Mackenzie, said that while onshore energy production is a minor part of the UK’s overall supply, domestic projects such as the West Newton field could help to plug the production gap as North Sea reserves diminish.