Sajid Javid has said he has no doubt that the Conservatives, if returned to power, will agree and finalise “a very ambitious, deep and comprehensive” trade deal with the EU by the end of next year.

The language is reminiscent of the Theresa May era and appears to suggest the Conservatives have pivoted away from Boris Johnson’s promise weeks ago of a “super Canada-plus” deal and are now back to close alignment with the EU – something Eurosceptics are vehemently against.

Can a comprehensive deal be done by the end of 2020?

The majority of commentators think this is highly unlikely, but the answer depends on the definition of a trade deal.

Sam Lowe, a senior research fellow at the Centre for European Reform, is one who believes it is possible. “The single biggest underpriced thing in this whole debate about Brexit is that Johnson and the EU might actually get a trade deal done by 31 December 2020,” he said. “It’s not that I am pushing this as a likelihood, I just think it’s possible and it could catch people off-guard.”

He said Johnson’s target was clear and simple: to extricate the UK from the single market and customs union, without much regard for the barriers to trade it would create. The EU could move quickly to get such a deal done.

However, others think Johnson, if he wins a majority, will pivot to a deal that aligns the UK with the EU far more closely than he has said to date.

“I think Johnson will come under enormous pressure to extend the transition period and I think he will,” said one well-connected former senior civil servant. “The worry for him without a transition extension is to risk getting a really bad deal after having ‘got Brexit done’.”

What would an ‘ambitious, deep and comprehensive’ trade deal look like?

Theresa May talked of “the broadest and deepest possible partnership, covering more sectors and cooperating more fully than any free-trade agreement anywhere in the world today”.

Catherine Barnard, a professor of European law, told a recent select committee hearing that it was unlikely a full deal could be achieved by the end of 2020 but it might be possible to conclude a single strand of trade talks.

“It may well be that you see a series of agreements staggered over time, and the easier one to conclude would be on goods,” she said. “It is in the EU’s interest to have an agreement on goods quickly, because the EU has a trade surplus with the UK in goods.”

Would this be enough to ‘get Brexit done’?

Any deal would be likely to be good for the Conservatives. The leave campaign’s mission was “taking back control”.

Would there be another cliff-edge?

Yes. Lowe predicts that having got Brexit done, the Conservatives would seek to “phase in” arrangements to cushion the economic shock and disruption for business.

“You would start with the status quo in 2021 and phase in the new arrangements,” Lowe said. This would be mean a transition or implementation period that could last years.

What would happen to the rest of Brexit if the only deal at the end of 2020 is on goods?

A security deal is also expected. But agreements are needed on a whole range of other issues: regulatory standards, mutual recognition of qualifications, defence, the Galileo satellite system, travel, transport, haulage, the rights of British nationals in the EU, reciprocal health and social welfare arrangements, continued cooperation on research and development in science, medicine and education.

If a rushed approach is pursued, Lowe expects the EU will make the deal contingent on an institutional framework agreement being signed simultaneously.

This would be an overarching arrangement that could enable talks to continue on other strands but with broad agreement on areas such as justice and home affairs, research cooperation and security and defence. The danger is that this could tie up negotiations for years.