The UK and EU are preparing to hit new Russian gas projects with sanctions if the Kremlin orders an attack on Ukraine, the first time Europe has weighed targeting a sector it relies on for 40 per cent of its gas imports.

The plans, being drawn up with US support, would severely curtail financing and technology transfer for new gas projects, according to people briefed on the discussions.

The sanctions being considered reflect concern over a potential Russian invasion of Ukraine following Moscow’s deployment of more than 100,000 troops near the border with its neighbour. The measures would form part of a wider package of potential economic measures, with the severity to be adjusted depending on the scale of any Russian offensive, people close to the discussions said.