However, the 57-year-old UK businesswoman has also said Britain must be closely aligned with the bloc – while urging fellow campaigners to channel their energies into “more immediate concerns”. Ms Miller incurred the wrath of Brexiteers across the nation after launching legal challenges against the Government on two separate occasions.
Six years ago, the High Court ruled the Government must legislate to invoke Article 50, which is the mechanism by which a member state quits the bloc.
In 2019, she tried to stop Boris Johnson from proroguing Parliament – and while her bid was dismissed by the High Court, days later the Scottish Court of Session ruled such the PM’s move was unlawful, a decision which was subsequently upheld by the Supreme Court.
Ultimately Mr Johnson opted to dissolve Parliament and call a general election, as a result of which he won an 80-seat majority.
However, in an op-ed for The Independent, Ms Miller gave her clearest indication yet that she was ready to move on.
She wrote: “As a realist, rejoining the European Union is a non-starter. This would only be possible if the other side had the door open.
“Boris Johnson’s dreadful behaviour as Prime Minister means that door is firmly shut for the foreseeable future.”
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Highlighting the importance of the economy, Ms Miller claimed Britain would have a worse recession than other countries as a result of leaving the UK, citing labour shortages and new barriers to trade.
She warned: “The combination of Covid and Brexit means all leading indicators point to more economic pain and despair ahead.
“This is confirmed by the International Monetary Fund’s recent findings that the UK’s poorest households are already among the hardest hit in Europe by the cost of living crisis.”
However, Ms Miller made it clear she was far from ready to turn her back on the EU.
She said: “It is time for the UK to sit down with EU officials and find common ground in areas that will benefit both sides.
“That means establishing areas of qualification and financial equivalence while being honest about free movement to address staff shortages in almost all sectors of the UK economy and public services.”
She said: “We often forget the genesis of the EU – ever-closer cooperation in Europe was a plan for peace.
“As the global tectonic plates shift and worrying alliances rise, the UK must remain close with the EU in providing peace and security around the world. This is so much bigger than the navel-gazing of arch-Brexiteers.
“They are cultishly obsessed with turning legitimate debate about our country’s future into an excuse to say anyone who points out the problems with leaving the EU is unpatriotic.”
Identifying climate change as the biggest problem for everyone concern, Ms Miller said: “We should be seeking equivalence with EU standards, reducing red tape in food trade.
“The UK must reiterate our climate commitments as non-negotiable by reinforcing our endorsement of Cop26 objectives.
“We must work with EU and G7 partners to support less developed countries and adapt to a warming planet – otherwise, mass migration of millions will affect us all.”