Boris Johnson will break his pledge not to extend the Brexit 'transition' period, the EU's trade chief predicted yesterday.

In a highly provocative intervention, EU trade commissioner Phil Hogan insisted Mr Johnson would cave and agree to keep Britain locked inside the bloc's single market and customs union beyond the end of next year.

Referring to the prime minister's broken promise of getting Brexit done by October 31, he said: 'In the past, we saw the way the prime minister promised to die in the ditch rather than extend the deadline for Brexit, only for him to do just that.

Boris Johnson (pictured) will break his pledge not to extend the Brexit 'transition' period, the EU's trade chief predicted yesterday

Phil Hogan pictured petting a Salers bull as he visits the 25th Animal Breeding Summit on October 5, 2016 in Cournon, France. He insisted Mr Johnson would cave and agree to keep Britain locked inside the bloc's single market and customs union beyond the end of next year

'I don't believe prime minister Johnson will die in the ditch over the timeline for the future relationship either.'

As it stands, Britain will leave the EU's institutions on January 31, but will remain inside its single market and customs union during the 'transition' period, which is due to finish at the end of next year.

However, under the terms of the withdrawal treaty there is the option of extending it for up to two years.

Any extension would mean Britain continuing to accept freedom of movement and paying membership fees.

In a highly provocative intervention, EU trade commissioner Phil Hogan (pictured) insisted Mr Johnson would cave and agree to keep Britain locked inside the bloc's single market and customs union beyond the end of next year

Mr Johnson has ruled this out and even begun the process of making any more delays illegal.

But speaking to the Irish Times, Mr Hogan dismissed the move as merely a 'stunt'.

Phil Hogan and his acid-tongued attacks on Brexit and Boris Johnson The EU's trade commissioner has been an outspoken critic of the PM and Brexit: On Boris Johnson: 'Prime Minister Johnson's hero is Winston Churchill and he seems to view himself as a modern day Churchill. However, in the event of a No Deal Brexit, the UK government's only Churchillian legacy will be – 'never have so few done so much damage to so many'.' On Mr Johnson being an 'unelected PM': 'We should recall that the backstop was agreed by a prime minister who was democratically elected,' he said, referring to Theresa May. On Theresa May - and Johnson, Farage and Rees-Mogg, the 'three stooges': 'For an agreement to take place, the issue needs to be, as Michel Barnier said, 'de-dramatised'. The invisible border is essential for peace - don't listen to the Three Stooges [Johnson, Farage, Rees-Mogg], they don't know the first thing about it.' - September 2018, speaking as pressure mounted on Theresa May's government over the withdrawal agreement. On No Deal: 'Pain for everyone, but the worst pain will be felt by the people of the UK.' On Brexit realism: 'The penny is finally dropping.' Advertisement

He said: 'At first sight this seems very odd indeed. From our point of view it is important that we move from stunt to substance.

'It would be helpful if the focus was on content rather than timetables.'

Throwing down the gauntlet, he added: 'Too much of the debate in the UK over the past four years was based on the false notion that it is possible to make a clean-break Brexit while retaining all the benefits of EU membership.

'Now that the political deadlock at Westminster is broken the next phase of Brexit needs to be based on realism and hard facts.

'Any 'having our cake and eat it' rhetoric will not fly. Both sides need to proceed calmly and coherently.'

The Irishman will head up the post-Brexit trade talks alongside the bloc's chief negotiator Michel Barnier.

It comes after EU Commission president Ursula von der Leyen said she had 'serious concerns' about Mr Johnson's timeframe of striking a trade deal by the end of next year.

Either side can request an extension to the transition period, but the UK and EU must finalise any agreement on whether to do so by July 1 next year.

Mr Hogan said that the prime minister had delivered a 'very impressive' majority at the general election and should now 'show leadership and use that majority for the good of the nation'.

He also dismissed the idea that the UK can get the tariff and quota-free trade deal it wants without remaining tied to Brussels standards on goods.

He said: 'We all have to come to terms with the reality that Brexit means there will be two markets, not a single market.'

Many in Brussels believe the prime minister is 'tying his hands behind his back' by pledging not to extend the transition period (file image)

EU officials say only a 'bare bones' trade deal will be possible in the 11-month window after Britain leaves on January 31.

It opens up the possibility of a new economic 'cliff-edge' at the end of 2020 if the transition is not extended and both sides fail to reach a trade deal by then.

Many in Brussels believe the prime minister is 'tying his hands behind his back' by pledging not to extend the transition period, and that they may be able to force him into making concessions to meet the target.

One EU diplomat said: 'Given the difficult nature of negotiations and the risk of another cliff edge at the end of 2020, it doesn't seem very logical to immediately close the door to an extension.

'If you deliberately tie your hands behind your back, you better make sure you can do a David Copperfield [the American escape artist].

'Otherwise you might run out of options when the heat starts to rise during negotiations.'