NICOLA Sturgeon has urged Boris Johnson to stay in Glasgow "for as long as necessary" to secure a decent COP26 climate deal.

The First Minister said the first draft of an agreement, published this morning, "is a start, but it must be the floor – not the ceiling". 

The draft calls on countries to strengthen their emissions-cutting plans in the next year in a bid to keep a goal to limit warming to 1.5C within reach.

It also calls for faster phasing out of coal and subsidies for fossil fuels - a first for a UN deal - but there is likely to be strong resistance to this from some countries and it could be taken out of any final agreement.

Developing countries and campaigners have also raised concerns over the provision of finance for poorer nations to cope with the impact of climate change.

Ms Sturgeon's plea came as the Prime Minister arrived back in Glasgow to urge international negotiators to "pull out all the stops". 

Scientists have warned that keeping temperature rises to 1.5C, beyond which the worst impacts of climate change will be felt, requires global emissions to be cut by 45 per cent by 2030, and to zero overall by mid-century. 

However, countries' plans for this decade leave the world well off track.

In a statement, Ms Sturgeon said: “The draft cover text is a start, but it must be the floor - not the ceiling. 

"The imperative for leaders now - on climate finance and the pathway to 1.5C - is to negotiate the ambition significantly upwards. 

"It must not be watered down. 

"It is vital that the world emerges from COP 26 with 1.5C well and truly alive, and closing the finance gap is key to that. 

"It is also a moral obligation developed countries owe to those less developed and most vulnerable to the impact of climate change.

“I welcome the Prime Minister’s return to Glasgow today, and urge him to stay for as long as necessary until a deal is done. 

"As has been the case all along, I will do everything I can to assist and support these efforts.

“This is a moment that future generations will judge. 

"Either we will be judged to have failed in the face of climate catastrophe or, alternatively, to have taken a decisive step towards sustainability for our planet. 

"It must be the latter. 

"In the words of a Marshall Islands minister I met yesterday - 'for countries like mine, we don’t have many COPs left - the time to act is now'.”