The Metropolitan police have confirmed that their officers would arrest the WikiLeaks founder Julian Assange if he left the Ecuadorian embassy in London to go to hospital for a medical examination.

Ecuador’s foreign minister, Ricardo Patiño, said Assange, who has been living in the embassy for more than three years, should be given safe passage to hospital for an MRI scan to help diagnose a pain in his shoulder.

The Foreign Office said Assange, who is subject to a European arrest warrant over an allegation of rape in Sweden, will not be prevented by the British authorities from receiving medical treatment. But it said questions over his arrest were a matter for the Met, which this week scaled back its costly 24-hour surveillance of the embassy.

Britain unmoved by Ecuadorian request to give Julian Assange 'safe passage' for MRI scan Read more

Scotland Yard confirmed that Assange would face arrest if he stepped outside the embassy, even if a mobile MRI scanner were parked outside the building in Knightsbridge, central London.

Assange, an Australian national, sought political asylum at the embassy in June 2012 to avoid extradition to Sweden. His American lawyer, Carey Shenkman, accused Britain of forcing Assange to “choose between the human right to asylum and the human right to medical treatment”.

At a press conference in Wednesday in the Ecuadorean capital, Quito, Patiño read from a letter by Assange’s doctor. The Justice for Assange Campaign released an edited version of the letter, dated 14 August. It quoted Dr Wood as saying: “He has been suffering with a constant pain to the right shoulder region for the past three months [since June 2015]. There is no history of acute injury to the area. [...] I examined him and all movements of his shoulder (abduction, internal rotation and external rotation) are limited due to pain. I am unable to elicit the exact cause of his symptoms without the benefit of further diagnostic tests, [including] MRI.”

The full text of the letter has not been released. A source at the Foreign Office confirmed that the Ecuadorian ambassador to Britain raised Assange’s medical concerns at a meeting with British officials last month. But it is understood that the Foreign Office has not received a copy of the doctor’s note.

Facebook Twitter Pinterest Ricardo Patiño, Ecuador’s foreign minister, speaking during a press conference in Quito. Photograph: Jose Jacome/EPA

Medical experts said Assange would have to leave the embassy to get an MRI scan, but a mobile scanner could be driven to the street outside the embassy.

Prof Stephen Keevil, a former president of the Institute of Physics and Engineering in Medicine (IPEM) and head of magnetic resonance physics at Guy’s and St Thomas’ NHS foundation trust, said: “An MRI scanner is a big piece of kit. It is not something you could carry into the building itself.”

But he added: “There are portable MRI scanners in the back of trucks and there are companies who provide mobile MRI services. I don’t know what the surroundings of the embassy are like, but if there’s a delivery entrance it would be perfectly possible to drive a truck with an MRI scanner in it and he [Assange] could walk in. Hospitals hire them on a daily basis.

“They probably cost in the order of thousands of pounds per day to hire, but not tens of thousands. I appreciate that if he had to come out of the embassy on to public ground to get there then that would be a problem.”

Asked whether Assange would be allowed to leave the embassy to enter a mobile MRI scanner, a spokesman for the Met said its operation to arrest Assange continued. It said: “Should he leave the embassy, the [Met] will make every effort to arrest him. However, it is no longer proportionate to commit officers to a permanent presence.”

Keevil pointed out that it might be possible to assess Assange’s condition using ultrasound equipment, which could be taken into the embassy. “Obviously there are other technologies that are more portable, ultrasound being the obvious one,” he said. “A quick look-see with ultrasound might be useful, but if the clinical view is that MRI is needed, that would not be supportable.”

A IPEM spokesman said an MRI scan would provide higher-resolution images and in general depict soft tissue problems more clearly than ultrasound.