I'm furious about having to mount Brexit legal challenge, says Gina Miller
The investment manager also predicted that Westminster would become the new Brussels.
The woman who brought the successful legal challenge against the government has hit out at Remain-voting politicians for failing to back her up.
Speaking at the Advertising Week conference in London, Gina Miller made a thinly-concealed attack on Jeremy Corbyn.
"As a Labour party supporter I’m furious, because I don’t think I should have had to bring this case," she said.
And she hit out at other Remain-voting politicians, saying: “I’m also disappointed that, having done so, having put my head above the parapet, others didn’t join me.
"They were very happy to do so quietly, behind closed doors… because of the very febrile environment that existed. I understand why they didn’t join me but I am disappointed."
Miller, an investment manager, also predicted that Westminster would become the new Brussels, with the UK parliament soaking up the blame that was previously directed at the European Union.
"If you no longer have Brussels to blame, then Westminster takes its place," she said.
"Is there then a possibility that we will see the tribalism that is happening, that all of the nationalism then becomes more localised and now becomes community-based so suddenly Manchester decides they are Mancunians and they become very much that tribe? Could we see it coming down to that level? I think we can."
Miller was a surprise guest at Adweek just over a week before the UK Government plans to invoke Article 50 of the Lisbon Treaty and trigger two-year-long divorce talks with the EU.
She told the audience that her main concern now was that Theresa May and a handful of Conservative politicians would override parliament and personally decide which EU laws should be kept and which should be discarded.
She said: "I was fighting against the use of the Royal Prerogative. We’re now going into Brexit where I see very much that power will reside with a few in Westminster. They will override parliament and use this Henry VIII clause where secondary legislation can be used to override primary legislation.
"What I can see happening is that all of the European acts will be brought in under this Great Repeal Act and then it will be the executive – literally a handful of ministers and the prime minister – who will decide on our futures and decide which rights to keep, which laws we keep.
"So I’m particularly worried about the process over the next two years actually diminishing parliamentary sovereignty and MPs powers, and it very much sitting with the executive and the prime minister. And I think this is something we should all be very alarmed about."