Donald Trump is a “very transactional” president, whose repeated demands on Iran must be seen in this context, one of Keir Starmer’s most senior ministers has said in an unusually blunt UK assessment of relations between the countries.

Asked about the US president’s threats of some sort of retaliation against allies who do not supply ships to try to free up the strait of Hormuz, Pat McFadden, the work and pensions secretary, said the UK was not obliged to agree to every US request.

After Trump again criticised the UK for a perceived lack of enthusiasm in helping the US-Israeli war against Iran, McFadden said it was important to separate the US president’s “rhetoric” from the more important issues.

In an overnight interview with the Financial Times, Trump reiterated his frustration at the UK for not sending ships to the strait of Hormuz, the vital sea freight passage that has been all but closed by Iranian retaliatory attacks.