The President of the European Commission is an alcoholic who binges on gin and leaves his ambitious but unelected deputy to govern, according to explosive new claims.

Jean-Claude Juncker - one of the most powerful men in Brussels - has been spotted stumbling around and unable to walk at the recent NATO summit.

He has repeatedly denied claims that he is an alcoholic and insisted that his sometimes shambolic appearance is down to chronic back pain known as sciatica.

But in an explosive new account, a Brussels insider says that he had heard the EU politician is 'a little too fond of the bottle'.

And Mr Juncker has left his ambitious and unelected chief civil servant Martin Selmayr - dubbed 'the monster' - to run the Commission, it is claimed.

Writing in The Spectator, Jean Quatremer - a French journalist who has covered the EU for years - says Brussels is awash with talk of the President's out-of-control drinking.

The EU Council President (pictured being helped along as he stumbles at the NATO summit earlier this month) has been accused of being an alcoholic who binges on gin and leaves his ambitious but unelected deputy to govern, according to explosive new claims

Mr Juncker (pictured being helped along at the NATO summit earlier this month) has always strongly denied claims he is an alcoholic

Mr Juncker was also photographed unable to climb the steps to the podium and being pushed around in a wheelchair at last week's NATO summit (pictured) - raising questions about his health and ability to govern

He wrote: 'Numerous people, in Luxembourg, in Brussels and in European capitals, can attest to several examples of Juncker drinking.'

He said that one former minister told him: 'When a bailiff brings him a glass of water at a council of ministers, we all know it's gin.'

WHAT IS SCIATICA? The term sciatica describes the painful symptoms when the sciatic nerve, which runs from your hips to your feet, is irritated due to something pressing or rubbing on it. The most common cause of sciatica is a slipped disc – which is when a soft cushion of tissue between the bones of your spine pushes out. Other causes include a back injury, spinal stenosis (a narrowing of the part of your spine where nerves pass through) and spondylolisthesis (when one of the bones in your spine slips out of position). If you have sciatica, your bottom, backs of your legs and/or feet and toes may feel painful (the pain may be stabbing, burning or shooting); tingly (like pins and needles), numb and/or weak. Source: NHS England Advertisement

Mr Juncker was photographed stumbling, unable to climb the steps to the podium and being pushed around in a wheelchair at last week's NATO summit in Brussels.

The meeting was a crunch showdown between Donald Trump and his defence partners - including many in the EU - after the US President had threatened to tear up the defence and security alliance.

Mr Juncker, 63, insisted that he was not drunk - and blamed his appearance on his back pain.

In a scathing assessment of his account, The Spectator piece states: 'But the "sciatica" explanation does not really stand up to scrutiny.

'It would suggest Juncker suffered agonising back pain, but he did not seem to be in any discomfort.

'The video shows him smiling, laughing, talking and kissing his partners as they helped him walk.'

It went on: 'The other explanation — and the assumption of a great many in Brussels — is Mr Juncker is a bit too fond of the bottle. Which he constantly denies.'

At a 2015 summit in Riga in Latvia, Mr Juncker welcomed the Hungarian Prime Minister Viktor Orbán with a shout of 'The dictator is coming!' and then a playful slap to the face, according to the account.

While the Belgian Prime Minister Charles Michel was greeted with a kiss on his bald head.

Jean-Claude Juncker (pictured sharing a beer at the Bavarian parliament in June) has been accused of enjoying the bottle too much

Some commentators claim that Jean Claude Juncker (pictured at a summit with his then aide Martin Selmayr late last year) has left the ambitious and unelected chief civil servant - dubbed 'the monster' - to run the Commission

Mr Quatremer says that while these antics have been put down to Mr Juncker's boisterous personality, they raise serious questions about his health and suitability for office.

And he said that while the elected EU President looks unable to govern, Mr Selmayr - who is dubbed the monster because he can work at all hours and is known for his brutal tactics - has been quietly taking over the reins of power.

He wrote: 'The deterioration of Juncker combined with the power of Selmayr indicates an unusual set-up with the President as the puppet.

'Pull back the gin-soaked curtain and we may find the real influence is wielded by Selmayr, an unelected and unaccountable Eurocrat.

Juncker is often pictured with a glass in his hand. He raises a toast to Angela Merkel in 2010

An aide pours out a glass of red for Juncker as he attends an European finance ministers meeting in Brussels in 2011

'Mr Juncker's spokesman insists there is "no anxiety whatsoever about Juncker's ability to work hard, as he always does".

Mr Juncker hit back at the reports of his drinking and denied the allegations when speaking to reporters yesterday.

Asked directly if alcohol played a role in his stumbling at NATO, he said: 'I'm really impressed by the interest some people are taking in these not even marginal issues and I am asking for respect.'

He added: 'I had sciatica and moreover I had cramps in my legs' adding that he 'laughed at the pettiness' of what was being said about him.