Boris and Carrie Johnson walked Rome’s iconic Spanish Steps last night ahead of the G20 summit.

Mr Johnson warned world leaders ‘the future of civilisation is at stake’ and compared climate change to the fall of the Roman Empire as he arrived in the Italian capital yesterday.

The couple took in the sights of Rome last evening as they walked up the Spanish Steps. 

The Prime Minister gave an apocalyptic vision of the future and said society could return to the dark ages with ‘terrifying’ speed, as he desperately tried to build momentum ahead of the COP26 summit next week.

Johnson gave an extraordinary warning about the danger of future generations falling into illiteracy. He even suggested that cows could become smaller.

He argued that after the collapse of Rome, civilisation even lost the ability to draw properly – saying ‘our children, grandchildren and great grandchildren’ could face food and water shortages.

Boris Johnson walks the Spanish Steps with his wife Carrie ahead of the G20 summit

Boris Johnson and Carrie Johnson walk the Spanish Steps together in preparation for the G20 summit

At one point, Mrs Johnson looked down at the steps

Mrs Johnson bent down

Mrs Johnson knelt on the steps and her husband looks around.

The Prime Minister yesterday gave an apocalyptic vision of the future and said society could return to the dark ages with ‘terrifying’ speed, as he desperately tried to build momentum ahead of the COP26 summit next week

The Prime Minister yesterday gave an apocalyptic vision of the future and said society could return to the dark ages with ‘terrifying’ speed, as he desperately tried to build momentum ahead of the COP26 summit next week

These comments were made amid concerns that the Glasgow gathering might end up being a damp squib.

China’s premier Xi Jinping has confirmed that he will not attend the event in person, although he will make a speech by video link.

Russian President Vladimir Putin is also shunning the summit along with Brazil’s Jair Bolsanaro.

Speaking to reporters en route to the G20, Mr Johnson said: ‘Humanity as a whole, at half time is about 5-1 down.

“We still have a lot to do, but we can do it.

‘We have the ability to equalise, to save the position, to come back but it will take a huge amount of effort.’

In a long description of the tragedy of the Roman Empire, Mr Johnson said ‘things can go backwards as well as forwards’.

‘Unless we get this right in tackling climate change we could see our civilisation, our world, also go backwards and we could consign future generations to a life that is far less agreeable than our own.’

The couple, who are expecting their second child together, walked the Spanish Steps

The G20 summit begins today

The couple, who are expecting their second child together in the next few months, walked the Spanish Steps before the G20 summit began today

Mr Johnson yesterday delivered an extraordinary warning that generations to come could slump into illiteracy - and even suggested cows could get smaller

Yesterday, Johnson warned that future generations could fall into illiteracy. He even suggested that the size of cows could increase.

Mr and Mrs Johnson held hands as they walked down the Spanish Steps accompanied by an entourage

As Mr. and Mrs. Johnson walked down the Spanish Steps, they held hands. Their entourage accompanied them. 

Boris made the comments as he arrived in the Eternal City for a G20 summit where he is desperately trying to ratchet up support for a breakthrough agreement to be made at COP26

Boris made these comments as he arrived at the Eternal City to attend a G20 summit. He is desperately trying to get more support for a breakthrough agreement at COP26.

The Prime Minister is said to have become much more environmentally conscious since he met his wife Carrie Johnson (pictured)

According to reports, the Prime Minister has become more environmentally conscious since meeting his wife Carrie Johnson (pictured).

COP26 begins in Glasgow on Sunday and will look to build on agreements made at the Paris climate summit in 2015 where nations agreed to try to keep global heating to below 1.5C

COP26 will begin in Glasgow on Sunday. It will build on the Paris climate summit’s 2015 agreements, where nations committed to keeping global warming below 1.5C.

The Prime Minister's comments come at a time where some have claimed that the absence of China and Russia's premiers will make COP26 a damp squid

The Prime Minister’s remarks come at a time when some have claimed that the absence China and Russia of their premiers will make COP26 a damp fish.

He went on: ‘We could consign our children, our grandchildren, our great grandchildren to a life in which there are not only huge movements of populations and huge migrations, but also shortages of food, shortages of water, of conflict caused by climate change and there is absolutely no question that this is a reality that we must face.’

Mr Johnson said after Roman civilisation humanity became ‘far less literate’.

‘Look at evidence of the decline and fall of the Roman Empire if you doubt what I say, when Rome fell humanity became far less literate overall, people lost the ability to read and write, they lost the ability to draw properly, they lost the ability to build in the way the Romans did.’

He said: ‘Things can go backwards and they can go backwards at a really terrifying speed.’

COP26 begins on Sunday at Glasgow’s Scottish Event Campus (SEC) and will welcome 30,000 delegates, 10,000 police and as many as 200,000 protesters for the 13-day conference.