Humza Yousaf has triggered a diplomatic row by meeting Turkey's president without a UK official present, with the Foreign Secretary now threatening to withdraw further support.

In a letter to the SNP Constitution Secretary Angus Robertson seen by the BBC, Lord David Cameron warned against any repeat of the First Minister’s breach of protocol.

Ms Yousaf met Recep Tayyip Erdogan at Cop28 in Dubai earlier this month, saying the pair had discussed the climate crisis and the “humanitarian crisis in Gaza”.

The First Minister did so without an official from the Foreign Office being present.

Mr Yousaf also advocated a ceasefire in the Israel-Hamas conflict in Gaze, which is not the UK Government position, and which appears to have concerned London.

The Scottish Government source said a last minute change at Cop28 was to blame rather than a calculated snub and any threats were "misguided". 

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However the BBC said it had seen a letter which Lord Cameron, who returned to the cabinet as foreign secretary last month, had written to Mr Robertson complaining about the matter.

Lord Cameron said the Scottish Government had assured the Foreign, Commonwealth and Development Office (FCDO) that it would give "sufficient advance notice" of the meeting.

He said this was to allow one of his officials to attend the meeting but this "was not done".

He went on: "The absence of an FCDO official at this meeting contravenes the protocols in our guidance on FCDO support to devolved government ministers' overseas visits.

"Any further breaches of the protocol [that] ministerial meetings have a FCDO official present will result in no further FCDO facilitation of meetings or logistical support.

"We will also need to consider the presence of Scottish government offices in UK government posts."

The BBC quoted a UK Government source saying Lord Cameron, who won the 2014 independence referendum before quitting after losing the Brexit vote, wanted to take a “harder line” approach than his predecessor at the FCDO James Cleverly. 

Mr Cleverly made a similar threat after Mr Yousaf met the Icelandic PM in August, again without UK diplomats present.

A UK government source said Lord Cameron’s letter was an "escalation" over the issue.

Although the Scottish Government did inform the FCDO of the location of the meeting, this was not done “until it was too late", leading to a move that "undermined UK foreign policy".

The source said the relevant FCDO guidance, which dates from April,, made clear that the UK government would expect an official to be present.

A spokesperson for the First Minister said: “The Scottish Government had no difficulty with an FCDO representative attending the meeting, and indeed the relevant UK official was made aware of it and invited.

"These were exactly the same arrangements as for other meetings that the First Minister had with governments of other countries at Cop28, at which the FCDO official was present.

"However, the nature of events such as COP is that timings can change at the last minute, and the FCDO representative was elsewhere at the time it was convenient for the Turkish president to meet.

“Any threat by the UK Government to curtail the Scottish Government’s international engagement is misguided and would work against Scotland’s interests.

“We are more than happy to discuss with Lord Cameron the continuing support of the FCDO in facilitating the work that Scottish Ministers undertake in delivering for Scotland overseas.”

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A UK Government spokesman said: “Foreign affairs is reserved under the Scotland Act and in such turbulent times, the need for the UK to speak on the world stage with one consistent voice is more important than ever.

“Our embassies and high commissions overseas have a strong track record of working collaboratively with the Scottish Government to promote the interests of the whole UK.

“We hope that we can resolve this without the need for further action, including the possibility that we no longer host Scottish Government offices in UK Government posts.”

Mr Yousaf has already been criticised from within his own party over the meeting.

The Kurdish-born Glasgow SNP councillor Roza Salih said she was "disgusted" by the Yousaf-Erdogan meeting, as Turkey had stepped up attacks on Kurdish groups in Syria.

Addressing Mr Yousaf on Twitter/X, she wrote: “Our politicians & half of the population are imprisoned by him and you shake his hand. I did not expect this from a FM that says he respects human rights.”

In response to Cllr Salih's criticism, Mr Yousaf said he would not stop meeting world leaders.