UK Prime Minister Rishi Sunak is today said to be reconsidering his decision to miss the COP27 climate-change conference.
This comes after after ex-PM Boris Johnson indicated he could attend next month's event - a move seen as "potentially explosive".
At the end of last week, Mr Sunak was accused of "a failure of leadership", after No.10 said he would not be at the summit in Egypt which runs from November 6 to 18.
Opposition parties and environmental groups said his decision suggested the government was not taking the climate crisis seriously enough.
Downing Street said the PM had "other pressing domestic commitments, including preparations for the autumn budget on November 17.
The Times says today that Mr Sunak is still prioritising his preparations for the budget, but it adds that there is an outside chance that he will make a fleeting appearance at the talks in Egypt if progress is made on key tax and spend decisions.
Extraordinary twist
The row over Mr Sunak's refusal to attend COP27 took an extraordinary twist on Saturday night when it emerged that Mr Johnson was is planning to attend the event.
The Guardian reports that several sources said that Mr Johnson was intending to go to Egypt meeting to show his solidarity with the battle against the climate crisis.
The newspaper adds that Johnson's attendance would be potentially explosive - just days after Sunak took over as prime minister and decided he did not have time to attend.
It continues: "Johnson's involvement would be seen as both an implicit criticism of Sunak for not going and an attempt to maintain and bolster his profile just a week after he abandoned his own attempts at a dramatic comeback to No.10."
Among politicians who will be at the conference are US President Joe Biden and Scotland's First Minister Nicola Sturgeon, but King Charles will not be joining them.
When former PM Liz Truss entered Downing Street, it was announced the King would not attend. That position has not changed under Mr Sunak.
Conference coming to King
But the BBC says that, if King Charles cannot go to the COP27 climate event, then at least some of the conference will be coming to him.
The King is to host a pre-conference reception at Buckingham Palace on Friday, bringing together 200 business leaders, politicians and campaigners.
The PM is to attend the Buckingham Palace reception. He is expected to speak, alongside guests discussing practical measures to tackle climate change.
Buckingham Palace said the event was taking place to mark the end of the UK's hosting of COP26.
King Charles has been a longstanding campaigner on protecting the natural environment and has warned of the dangers of climate change.
As the Prince of Wales, he was a leading figure at last year's COP26 climate conference in Glasgow, giving an impassioned speech about the urgency of the challenge and the need for the global response to be put on a "war-like footing".
Royal sources have denied that the King has been frustrated or disappointed about not attending COP27 - saying that he accepts that as monarch he has to consider the advice of government ministers.