Saudi Arabia is under mounting international pressure over the blogger Raif Badawi, whose public flogging has been postponed for a second consecutive week after a medical assessment.

Protests and vigils were held in public places and outside Saudi embassies across the world on Thursday, keeping up the momentum after a medical committee said he should not undergo a second round of 50 lashes on health grounds.

Amnesty International, which has adopted the liberal thinker as a prisoner of conscience, said that the committee, comprising about eight doctors, carried out a series of tests on Badawi at the King Fahd hospital in Jeddah on Wednesday and recommended that the flogging should not be carried out.

Badawi, 31, was sentenced last May to 10 years’ imprisonment and 1,000 lashes – 50 at a time over 20 weeks – and fined 1m Saudi riyals (£175,000). He has been held since mid-2012, and his Free Saudi Liberals website, established to encourage debate on religious and political matters in Saudi Arabia, is closed. He received his first 50 lashes on 9 January, but the punishment was not carried out a week later.

The postponement suggests that the Saudi authorities are not impervious to the wave of protests about the case. Philip Hammond, the foreign secretary, raised it with the Saudi ambassador to Britain, Prince Mohammed Bin Nawwaf Bin Abdelaziz, during an anti-terrorist conference in London on Thursday.

“We are seriously concerned by Raif Badawi’s case,” a spokesman said. “The UK condemns the use of cruel, inhuman or degrading punishment in all circumstances. The foreign secretary has raised the matter with the Saudi ambassador, and we’ve previously raised the case at a senior level with the Saudi authorities.” The Saudi embassy declined to comment.

Amnesty has accused the UK of being “muzzled” by its commercial and defence interests in the conservative kingdom.

Ensaf Haider, the blogger’s wife, said she was “relieved” he would not be flogged again on Friday, but remained concerned about his health.

“Instead of continuing to torment Raif Badawi by dragging out his ordeal with repeated assessments, the authorities should publicly announce an end to his flogging and release him immediately and unconditionally,” said Said Boumedouha of Amnesty International’s Middle East and North Africa Programme.

“Raif Badawi is still at risk. There is no way of knowing whether the Saudi Arabian authorities will disregard the medical advice and allow the flogging to go ahead.”

On 9 January Badawi was shown on a YouTube video being beaten in a square outside a mosque in Jeddah, watched by a crowd of several hundred who shouted Allahu Akbar (God is great) and clapped and whistled after the flogging ended. Badawi made no sound during the flogging and was able to walk unaided afterwards. His wife had said she feared he might not be able to physically withstand another flogging.

Earlier this week Amnesty – with the British Medical Association and Freedom from Torture – staged a conference of medical health professionals to discuss the ethical and practical challenges facing forensic physicians as they confront torture. Amnesty International UK’s Stop Torture campaign manager, Tom Davies, said: “Why are doctors in Saudi Arabia taking any part in a process that is clearly a vicious act of cruelty? “All medical professionals have a clear duty to avoid any involvement in acts of torture and cruel treatment whatsoever. Indeed, they should be reporting their suspicions that abuse is taking place if they come across it. “Rather than providing pre-flogging medical assessments, prison doctors in Saudi Arabia should refuse to participate in the calculated cruelty of Raif Badawi’s punishment.”