London: Gina Miller doesn't mind being called a "Remoaner''. It tells her that her opponents, the Brexiteers, are getting desperate, she says. That they don't have a plan.

"They still seem unwilling to be realistic," she says. "They think they're losing their 'win'.

"When people resort to name-calling, it's because they can't have a debate. It's the fall-back position for a lack of ability to debate or come up with an alternative."

Miller, a British investment manager and philanthropist, became well known (and, in some quarters, reviled) last year for leading the successful legal battle to make sure parliament had a say in triggering Brexit.

Gina Miller, a British investment manager and philanthropist, continues to fight for a soft Brexit. Bloomberg

She then organised a campaign to back candidates opposed to a "hard Brexit'' in this year's general election, and has continued to campaign in this vein.

She's one of the reasons it's not turning out to be a glorious northern summer for the Brexiteers.

They fear their dream of a quick, clinical, all-encompassing Brexit is being taken away from them.

One – influential Tory backbencher Charlie Elphicke – worried "we will end up in a Hotel California situation: you can check out but you can never leave".

Some campaigners fear their sought-for Brexit will be eventually revealed as a mirage. AP

Brexit godfather Nigel Farage claimed "the old alliance of big business and a Tory government is booming again".

He perceived a "new consensus" forming to undercut Brexit.

Nigel Farage, left, warns that 'establishment' forces are aligning to undermine the result of the EU referendum. AP

"For a nation to rise up against the establishment and secure a historic victory, only to have its hopes thwarted by an out-of-touch elite, is a recipe for dangerous division," he said.

So what has them so worried?

Brexit minister David Davis, left, and the EU's chief Brexit negotiator, Michel Barnier have seen early negotiations make slow progress. Geert Vanden Wijngaert

In a nutshell, it's not going well. A combination of poor preparation from the British government, and the sheer scale of the problem, are combining to create a strong headwind.

And meanwhile the clock is ticking down to a March 29, 2019, deadline, when the rules of the treaties that underpin the European Union say Britain is on its own, ready or not.

British expatriates living in Europe remain uncertain as to what their future holds. Getty Images

Last week the second round of Brexit negotiations in Brussels ended on a bum note, with the EU's chief negotiator Michel Barnier chastising his opponents for not knowing what they want.

"We make better progress where our respective positions are clear," he said.

British Trade Minister Liam Fox has hinted the Brexit transition may continue beyond the March 2019 deadline. Bloomberg

This week Barnier warned the stand-off over issues such as the rights of EU citizens in Britain, the problem of the Northern Ireland border, and the "divorce bill" settling accounts between Britain and the EU, would drag the first phase of talks into 2018.

This would mean even less time for the second phase: settling the relationship between Britain and the continent – on trade, customs, migration and a hundred other issues – before the March 2019 deadline.

Former Labour minister Denis MacShane believes Brexit 'will be a very limited exit and it won't be one that causes sustained economic problems for us'. Alamy

Meanwhile, at the start of the week the British government sprang leaks suggesting it was united on a post-Brexit "transition period" that would include free movement from the EU into Britain – and could last up to four years.

Trade Minister Liam Fox tried to reassure Eurosceptics that this was a "rounding error" compared with how long they had been waiting for Brexit.

The government has long flagged that Britain would gradually transit to its post-Brexit state, rather than adopt all new rules and regulations at once.

But this was a step further that outraged Eurosceptics. The government was adopting the language of the business lobby, who have – with increasing volume – been arguing for a gentle transition into Brexit over several years, during which free trade and free movement of labour are retained to avoid a "cliff-edge" moment (a phrase the government has tellingly adopted).

Immigration Minister Brandon Lewis insisted that free movement of labour "ends when we leave the European Union in the [northern] spring of 2019".

But Home Secretary Amber Rudd, Lewis' boss, explained that even if freedom of movement ends officially in March 2019, EU citizens will still be able to come to Britain to live and work if they register with the government. Essentially, not much will change, at least for a while.

The Brexiteers fear that two years will become four, four perhaps more, and their sought-for Brexit will be revealed as a mirage.

'We are a pragmatic nation'

Former Labour minister for Europe Denis MacShane, who has been pumping out books on Brexit for the last two years, had a new one out this month. Its title: Brexit, No Exit: Why (in the end) Britain Won't Leave Europe.

MacShane – very much not a Brexiteer – concedes that the result of last year's referendum does imply Britain leaves the EU.

But he identifies more than 20 other "Brexits'' apart from the one in the treaty – none of which need happen.

There's the single market, the customs union, foreign and security policy, human rights, farming, research, ratings agencies, professional qualifications … many ways in which Britain could still choose to be part of what MacShane hates calling "the European project".

Over a nice tuna nicoise salad he's whipped up in his Pimlico home, MacShane argues a minimal Brexit is possible, realistic and practical. He imagines a speech he hopes the prime minister – whoever it is – will deliver after Brexit.

"As of today, Britain has recovered its sovereignty. We are masters of our destiny. Only this our palace of Westminster will be where our laws are made. We have left the European Union.

"Now. We are a pragmatic nation, a trading nation, we believe in co-operation, we are open to foreign investment. Many European laws are ones we wrote. So for the time being I'm not proposing any significant rupture in our trading relationship with Europe."

MacShane thinks the problem of Northern Ireland – where a return to border posts would mean a serious threat to peace – will be the incentive to stay in the customs union.

He thinks pressure from the business lobby – which is finally starting to awake from its post-Brexit quiescence – will mean free movement of EU citizens remains, at least for a while, and the can could be kicked endlessly down the road.

"The negotiation that Britain needs is not with Europe, which is sitting pretty," MacShane says. "The negotiation that's needed is with the British people. Particularly the English."

As long as you deliver the supreme prize – sovereignty – the rest is up for grabs, MacShane says.

It may need some crisis before the tide turns,

"Frankly it would be helpful were Nissan or Toyota to announce [a factory] closure or Ryanair to say they couldn't fly any more," he says.

He's trying to encourage people to do little talks around the country, to conduct a little "Brexit audit" to gather stories of businesses and organisations that may be damaged by Brexit.

There's a precedent, he says. In 2014 Switzerland held a referendum to cap EU immigration. It proved a headache for the government, which couldn't find a way to enact the referendum without also leaving the single market. In the end, it finessed a law that granted job preferences to Swiss workers without imposing actual quotas.

"A lot of people would now accept that the implications of Brexit weren't spelt out [before the referendum]," MacShane says.

Rather than pressing for a second referendum, the parliament should press for a Brexit that hurts Britain the least.

Should – and will, MacShane says.

"I would love there to be a complete reversal [of Brexit], I expect that's difficult but I certainly think it will be a very limited exit and it won't be one that causes sustained economic problems for us," he confidently predicts.

'The best deal we can get'

Miller says there "must not be a disintegration of democracy as a result of Brexit, so the vote has to be respected".

She isn't pushing for a new referendum either. However, she believes the vote didn't preclude "the option to remain".

"We should be pushing for the best deal we can get from the EU, and then we compare that to where we are, and then there's a full and proper vote in parliament, and then whatever happens, happens."

What may happen is that Britain stays in its "transition phase" until its next election, which would be another opportunity to reverse or reinterpret Brexit, she says.

If there must be a deal, she wants Britain to have a status like Norway – outside the EU but inside the single market, allowing free movement of people, goods, services and capital. She believes the country could get it if it pushed for it. According to reports from the continent, it's a Plan B that Brussels is prepared to accept.

But Miller says she isn't growing in confidence. In fact, she's getting more worried that the Brexit process is already descending into farce, and the enormity of the challenge will just prove too much for Britain, which will fall off the cliff edge of a deal-less Brexit.

"Last week I had a meeting with an arch-Brexiteer. I said everybody accepts there's going to be an economic shock, will it be two or three years? He said 'No, no, no, we accept it might take 20 to 30 years'.

"And they're prepared to take that. They're prepared to sell out one or two generations of our country for the dream they think might happen. It's the most irresponsible politics I've heard of."