Plans by Gazprom to seize control of a major part of Britain’s gas supply triggered outcry in political circles. It was 2006, and the Russian state-owned energy giant had announced a bid for Centrica, the parent of British Gas. 

The move, which triggered a 25pc spike in Centrica’s share price, came just after Moscow had cut off gas supplies to Ukraine over a pay dispute – widely regarded as an act of aggression against an ally of the United States. 

At first, Russia’s bid for British assets seemed fruitless: Gazprom’s advance was refused by the Department of Trade and Industry in February that year. Officials warned the move would come under intense scrutiny amid fears it would jeopardise the security of UK energy supplies.

Two months later, however, Tony Blair intervened. The then-prime minister said he felt the block was a form of “economic patriotism” that went against his support for globalisation, reported the Financial Times. 

Alan Johnson, Industry Minister at the time, also expressed his support, saying: “Whatever the difficulties and challenges of globalisation, the answers will not be found in the stagnant waters of protectionism.”

MPs, meanwhile, warned about Vladimir Putin extending the “tentacles” of his energy companies and the security of energy supply if one company had so much control. 

It was then that Gazprom went quiet – but it followed through on ambitions to capture the British market. Its British supply arm now controls one fifth of the UK’s business gas market.

Lord Oates, Liberal Democrat spokesman for energy in the House of Lords, says: “They have pursued a very aggressive commercial strategy in the UK. It’s not just businesses – they’ve got lots of public sector organisations as well. They’ve clearly built up a very powerful position largely under the radar.”