Don't be fooled by the High Court ruling, Brexit will still happen for two reasons – Theresa and May

The real threat to the Government is that Parliament attaches conditions to its approval of Article 50 to influence the shape of the Brexit deal

The High Court’s ruling that the Government must consult Parliament before triggering the formal Article 50 exit process will raise the hopes of pro-Europeans who still believe that Brexit is a bad dream from which they will soon awake.

But they will be disappointed. Brexit will still happen, for two reasons – Theresa and May. The Prime Minister will make it happen. She believes that failing to leave the EU would be the ultimate betrayal of the public who voted for it in the referendum – many as a protest against the political class, so their sense of betrayal would be even greater if they were ignored. May is probably right to think that any political leader who defied the voters in this way would be punished with the loss of their job.

However, the ruling has made May’s already difficult task on Brexit even more problematic. True, the Government may win its appeal in the Supreme Court, which would allow May to trigger Article 50 on her timetable before the end of next March. But no one in Whitehall is taking victory for granted, and so ministers may have to win the backing of the Commons and Lords for starting the withdrawal process.

Although a small number of Europhile MPs and peers might seek to scupper the Brexit process by voting against Article 50 being invoked, a majority would almost certainly allow it to go ahead. MPs whose constituents had voted Leave and most unelected peers would be wary of denying the people’s will.

But they will feel emboldened by the High Court ruling to have a greater say on the substance of the Brexit talks rather than merely rubber-stamp the start of the process. So the real threat to the Government is that the two Houses attach conditions to their approval of Article 50 to influence the shape of the Brexit deal.

There might well be a majority in both the Commons and Lords for remaining in the single market, and making that a greater priority in the negotiations than curbing migration. May, the former Home Secretary, who some ministers say is still doing her old job as well as her day job, has interpreted the referendum as a mandate to put migration ahead of market access. She would not want her hands tied by Parliament on this central trade-off as she enters two years of talks.

She might try to head off such a nightmarish prospect through Parliamentary game-playing – for example, by trying to implement the courts’ edict to involve Parliament by offering a simple Yes/No vote on a government motion rather than bringing in full-scale legislation (even though it took a 1972 Act to take us into the then European Economic Community).

Another prospect looms into view – an early general election. If government whips advised May that Parliament could vote for single market membership, she might well seek an election to ask the public for a mandate for her negotiating goals, with cutting migration her number one “red line”. In effect, May would be asking the voters for the go-ahead to implement their referendum decision, and to stop Parliament thwarting it.

That would still be a high risk strategy. First, May might have to engineer a messy vote of no confidence in her own government to get round the Fixed-Term Parliament Act, which says the next election will be in May 2020. Then she would have to win the election.

She would, of course, start as the favourite against Jeremy Corbyn’s Labour Party, but would not be a normal contest, a choice between two leaders and of which party is trusted on the economy. It would be a “Brexit election”, and we know the country is split down the middle on that. The Liberal Democrats would fight the election on a Remain ticket and could take votes away from the Conservatives in key marginal seats.

The Prime Minister has insisted the election will not be until 2020 and is not someone who likes breaking her word. An election would add to the uncertainty caused by Brexit and there could be turmoil in the financial markets. But the High Court ruling has certainly made it more likely that the circumstances arise in which May changes her mind, and she sees an election as her best chance to deliver the referendum instruction.

Those who wish to keep the UK in the EU should not get too carried away by the High Court’s decision. It is not the end of the legal battle. The High Court in Belfast ruled the other way last Friday. May will be a formidable opponent, whether she wins or loses in the Supreme Court.

All the signs are that May will present Parliament with a take-it-or-leave it Brexit agreement in 2019. If MPs and peers judged it a bad one, they would still be under huge pressure to approve it because the only alternative would be no deal, with UK-EU trade covered by the tariffs of the World Trade Organisation.

The best strategy for pro-Europeans is not to try to throw a spanner in the Brexit works now by blocking Article 50. It is to put their energy into seeking a proper vote in Parliament or second referendum on the exit deal in 2019, with the option of staying in the EU still on the agenda.