Boris Johnson has been branded “childish” after he revealed plans to leave First Minister Nicola Sturgeon on the sidelines when the world’s largest climate change summit goes to Glasgow.

The pair clashed after Mr Johnson planted a union flag firmly in the Scottish Government’s turf in what looks like becoming an unedifying tug-of-war over who gets claim on hosting international talks on the future of the planet. 

At a Conservative Party conference fringe meeting, Mr Johnson said the union flag should stand out at all Westminster-funded policies and events.

He said: “I’ll tell you what we’ll do. We make sure, with every policy we pursue, with every investment we make in Scotland, then we put a Union flag on it.

“For instance, the COP26 climate change summit that’s going to be held ... the leaders of the entire world will come to Glasgow.”

He was reported as saying: “I guess I don’t mind seeing a Saltire or two on that summit, but I want to see a Union flag, I don’t want to see Nicola Sturgeon anywhere near it, because the Scottish Nationalist Party [sic] didn’t secure that summit in Glasgow, it was the United Kingdom government.”

The COP26 meeting, under the auspices of the UN, will decide the future direction of global efforts to avert the climate crisis.

It will take place in Glasgow in December 2020, with up to 30,000 delegates expected as well as leaders of most of the world’s governments, making it the biggest international summit to be hosted in the UK.

After months of behind-the-scenes preparations, the UK was confirmed earlier this month as co-host with Italy, where some preparatory meetings will take place, when other countries signalled their acceptance on Tuesday.

Yesterday a spokesperson for the First Minister hit out at the remarks and made it clear they did not intend to give up on driving one of their flagship policies. 

A spokesperson for First Minister said: “People will be deeply embarrassed to hear their Prime Minister acting so childishly. 

“It is right that the COP26 conference should come to Scotland given our leadership in climate action – we were one of the first countries in the world to acknowledge the global climate emergency and the Scottish Government has introduced the toughest targets in the UK to ensure our action matches the scale of our climate ambitions. 

“When it comes to issues of common concern such as climate change, the SNP Government are proud to play our part and work in partnership with other governments – something that Boris Johnson seems completely incapable of doing.”