Keir Starmer has convened the Cobra emergency committee to discuss Britain’s possible role in Israel’s war with Iran.

That probably means that Britain has received or expects to receive a request from America for assistance should president Trump decide to join the campaign.

So what could Britain contribute? And what will Starmer agree to?

The staging post

The key question is Diego Garcia, the Indian Ocean airbase that would be used to launch the main American strike.

By last month, the Americans had already mustered 10 heavy bombers on the island: six B2 Spirits, and four B-52s.

These are the only machines that can carry the GBU-57 Massive Ordnance Penetrator – the six-metre, 14-tonne bomb designed to destroy the underground Iranian enrichment centre at Fordow.