Gina Miller is taking the UK government to court in what has been described as the most important constitutional case in a generation. Picture: AP Photo/Matt Dunham.

A HAIRDRESSER, fund manager and a UK expatriate living in France are at the centre of a case described as the most important in a generation for Britain.

Former finance worker Gina Miller is leading the charge against the British government in a High Court battle over Brexit that centres around fundamental questions of democracy.

The group claims the UK government should not be able to trigger Article 50 — the process that begins the two-year time frame for exiting the EU — without a parliamentary vote.

However the government said it has “royal perorgative” which serves as a kind of executive order following the June 23 referendum that saw the UK vote in favour of leaving by 51.9 per cent to 48.1 per cent.

Ms Miller — who voted to Remain but insists it’s not a case of sour grapes as “we’re all leavers now” — said she had received threats for taking it to court.

“People are really frightened to put their heads above the parapet,” she told AFP.

“I myself have received death threats ... Apparently my head belongs on Traitors’ Gate.”

“Our business has been boycotted. It’s been quite vile. But I won’t be bullied because to my mind this is best for everyone, to have legal certainty”.

Hairdresser Deir Dos Santos, 37 and groups the People’s Challenge and Fair Deal for Expats also back the case which is being handled by prestigious firm Mishcon de Reya. Other claimants are unwilling to be identified for fear of abuse.

On Thursday, both pro-Brexit and pro-Remain demonstrators appeared outside the court.

Gina Miller, co-founder of investment fund SCM Private, is taking on the UK government but insists it’s not a case of sour grapes over Brexit. Picture: BEN STANSALL/AFP

Gina Miller, co-founder of investment fund SCM Private, is taking on the UK government but insists it’s not a case of sour grapes over Brexit. Picture: BEN STANSALL/AFPSource:AFP

The high stakes case cuts to the heart of a fundamental question raging in the UK parliament: Does the government have to get approval from MPs for the terms of the Brexit deal?

Pro-Brexiteers say no — that’s what the referendum was for. Others say there was no mandate for the type of Brexit that will be delivered and this needs to be voted upon.

Fundamental questions around border control, single market access and fair trade remain unanswered with even the Conservative party split on what the deal should look like — let alone the other 27 nations of the European Union who each have their own interests to consider.

Prime Minister Theresa May has remained elusive on the issue, saying only that “Brexit means Brexit”. She said MPs will be able to “discuss, debate and question issues” but there was no putting off the inevitable.

“We’re not asking ourselves what bits of membership we want to retain,” she said.

University College London professor Jeff King told Bloomberg the case is “one of the most important constitutional law cases ever decided.”

It could even lead to risks of lengthy delays or jail for MPs who ignore the court orders, the organisation reports.

An unwelcome site for British travellers as the pound sinks to less than one euro. Picture: AP Photo/Frank Augstein

An unwelcome site for British travellers as the pound sinks to less than one euro. Picture: AP Photo/Frank AugsteinSource:AP

Fears this week the UK could opt for a “hard” Brexit that could mean no single market access in exchange for complete border control have sent the pound to a 31-year-low against the US dollar.

On Thursday, Tesco removed grocery favourites like Marmite and PG Tips tea from sale online in a spat with Unilever who wanted a price hike to compensate for the falling pound.

The move sent consumers reeling with #Marmitegate trending online but is likely to be the first of many disruptions for consumers as Britain’s withdrawal from the EU occurs.

The High Court case will run until Monday. It’s being head by Lord Chief Justice Thomas, Sir Terence Etherton and Lord Justice Sales.