The YouGov poll released at 10pm on Tuesday 10 December 2019 forecasts a Conservative majority of 28 in the House of Commons. Press reports on Wednesday morning note that this is significantly down from the previous poll, which suggested a majority of 68. 

While the latest poll suggests that a Conservative majority government is still the most likely outcome, some commentators currently suggest that the possibility of a hung parliament cannot be entirely ruled out. The possible election outcomes could have very different implications for Brexit.

A Conservative majority would give Boris Johnson the mandate to 'Get Brexit Done' and to get his deal passed by the UK Parliament, perhaps even before the end of the year. If ratification by the European Parliament and Council were also to be in place before 31 January 2020, then the current 'Final Brexit Date' would remain as 31 January 2020. Any delay in ratification by both by the UK and EU might require a further extension, or alternatively might still conceivably trigger a "no deal" Brexit. 

The Conservative timetable for the trade deal that Boris Johnson has promised - 11 months - is very ambitious and it has been widely reported that the EU member states have signalled strong caution on that. To a great extent, the viability of the proposed timetable depends on the extent and ambition of any trade deal. Arguably, a basic "free trade" agreement, restricted to tariff arrangements for goods, might be concluded relatively quickly. However, if more extensive arrangements were sought (for example, in relation to services), then rapid agreement would appear far less likely. That would particularly be the case if (like the EU-Singapore trade agreement), a deal were to include any issues reserved to EU member states, in which case the EU ratification process could prove to be lengthy and complex.

Negotiating the full future relationship in advance of December 2020 would be a massive challenge, not least because the UK and EU would ned to come to terms on a raft of matters including, state aid, competition, employment standards, environment, climate change and tax. A deal would also have to encompass current areas of co-operation including, security, trade and data.

As we have seen with the current deal, deals are difficult to negotiate and a future trade deal will be no less challenging. Uncertainty on this point is amplified by the change of personnel on the EU side. The new EU Commission took office on 1 December, and conduct of negotiations on the future EU-UK trade relationship would fall to the new Trade Commissioner, Phil Hogan, a Fine Gael politician from the Republic of Ireland. Again as we have seen with the current deal, any future agreement (be that on withdrawal or trade), would have to undergo a complex process of EU ratification followed by implementation. 

The Conservative manifesto states that there will be no extension of the implementation period beyond December 2020 and this then represents that next potential 'cliff edge' and the point at which the UK would again face the possibility of a "no deal" Brexit. Under the Conservative manifesto the possibility of a no deal Brexit remains a very distinct possibility as the manifesto states that it wishes to keep the UK out of the single market and any form of customs union, and end the role of the ECJ. 

A hung parliament is very likely to alter the current Final Brexit Date and it might open the way for the UK to remain in the EU. Without a majority and with the DUP opposed to Boris Johnson's deal (their Manifesto sates that they do not consider that the current deal is in NI's longer terms interests), it is not clear how Boris Johnson would be able to secure Parliamentary approval for his deal. It then becomes likely that Boris Johnson would have to accede to hold a second referendum on his deal.

A Labour majority government would, their manifesto makes it clear, negotiate its own new Brexit deal and put it to a "final say referendum", with remain as an option on the ballot paper. The Labour manifesto promises this within six months of the election, so by summer 2020. A delay to this ambitious timetable is not inconceivable however.

Overall, the Labour manifesto proposals do appear more likely to be acceptable to the EU. The way the proposals have been set out contains inherent flexibility and the thread is alignment with EU. The manifesto states that Labour's new deal would include a permanent and comprehensive UK-wide customs union and close alignment with the Single Market. Labour also propose "dynamic alignment on workers' rights, consumer rights and environmental protections", although it is not clear what this means for free movement.

Labour, the Green party, Plaid Cymru and the SNP favour a second referendum, with "remain" as an option on the ballot paper. The Liberal Democrat manifesto does not contain this. The Liberal Democrat manifesto states that they would revoke Article 50; this is possible while the UK remains in the EU (currently before 31 January 2020), but it would be challengeable if it does not have parliamentary approval. However, this week the press reports that Jo Swinson has said that a bill for a second referendum is 'ready to go'.

It currently appears that if a Labour minority government is the outcome of the election, then the other parties that would favour a second referendum may now also include the Liberal Democrats.