Addressing Republicans in Philadelphia yesterday, Theresa May said Donald Trump had an obligation to accept US responsibility to take an active role in the world Mark Makela/ Reuters

Theresa May offered last night to help President Trump to prevent the West from being “eclipsed” by China as she urged him not to shirk his “obligation” to lead the world.

In a speech to a Republican congressional retreat in Philadelphia the prime minister matched parts of Mr Trump’s controversial foreign policy.

She criticised China’s increasingly “assertive” posture, promised to help to curb Iran’s “malign influence” in the Middle East and to do more to defend allies such as Israel in “tough neighbourhoods” while admitting that it was time to engage Russia in the search for peace in Syria.

Mrs May offered an updated edition of the special relationship, one that would be shorn of illusions about “making the world in our image” and without…