Cherie Blair was reportedly barred from attending a Foreign Office meeting with her client, the Maldivian foreign minister, in the latest twist in her legal battle against Amal Clooney over the fate of the islands' former leader.
Mrs Blair's firm, Omnia Strategy is representing the government of the Maldives over the imprisonment of deposed former President Mohamed Nasheed, while Mrs Clooney is working pro bono on the campaign for his release.
The UK Government is pressing for Mr Nasheed's release and Dunya Maumoon, the Maldives' foreign minister, was due to meet Huge Swire, the foreign office minister, last week to discuss the case.
Ms Maumoon requested Mrs Blair attend the meeting with her but Mr Swire refused, resulting in the meeting being cancelled, the Mail on Sunday reported.
A diplomatic source told the paper: "The usual protocol is for ministers of different governments to talk directly to each other.
"They do not need expensive lawyers to be present. Mrs Blair's presence at such a meeting would have been totally inappropriate.
"She – or anyone else – would just have got in the way. It suggests the Maldives government knows it is on very flaky ground legally. Why else would their foreign minister want a lawyer at her side?"
Mrs Clooney, whose husband is Hollywood actor George Clooney, has previously held talks with Mr Swire and met David Cameron earlier this year.
Mr Nasheed, the Maldives' first ever democratically-elected leader, ruled from 2008 to February 2012 when he was forced to resign following a mutiny by police and troops. He was jailed for 13 years for terrorism charges after a hasty trial at which no defence witnesses were allowed.
A Foreign Office spokesman said: "Minister Swire has met Foreign Minister Dunya Maumoon a number of times to discuss the situation in the Maldives.
"Along with the international community, the British Government has made clear its concerns about the shrinking of democratic space and independence of the judiciary.
"We continue to encourage genuine political dialogue between all parties and the release of all political prisoners, including former President Nasheed, to help re-establish confidence in democracy in the Maldives."