Huge anti-Brexit demonstration throngs central London

At least 100,000 people took to the streets yesterday as part of the largest ever demonstration of support for a new referendum over Britain’s final Brexit deal.

With more businesses poised to issue dire Brexit warnings this week and senior Tories already drawing up plans to soften Theresa May’s exit proposals, organisers of the march on Sunday said it showed Britain’s departure from the European Union was not a “done deal”.

A former aide to Margaret Thatcher, several Labour MPs and pro-EU campaigners from across Britain took part in the demonstration, marking two years since the Brexit vote. Organisers said that people from every region and walk of life were among those who took part in the march down Whitehall.

Conservative supporters marched alongside Labour voters and Liberal Democrats during the protest, which saw angry denunciations of the chaos that has ensued inside government since the Brexit vote. Labour’s leadership also came under pressure at the march for refusing to back a second public vote. There were chants of “Where’s Jeremy Corbyn” from the crowd. The Labour leader was on a visit to a Palestinian refugee camp.

Anger on the streets at the prime minister’s handling of the Brexit negotiations is being accompanied by a renewed push from industry to ensure that trade with Europe is not disrupted as a result of leaving.

More prominent manufacturing firms are set to issue warnings about Britain’s Brexit negotiations within days, after Airbus and BMW broke cover to say they could reconsider their UK investment plans unless a Brexit deal was reached keeping Britain closely aligned with Europe.

Senior Tory MPs are already warning that the government will face another parliamentary crisis over Britain’s post-Brexit trade arrangements within weeks unless May gives clear indications that she backs such a deal.

In a rare intervention, Lord Glendonbrook, the Conservative peer who ran the BMI airline for decades with a fleet of 45 Airbus aircraft, warned that the delays in securing a tariff-free deal were handing a “Brexit dividend” to Britain’s economic rivals in Europe. He said the government’s divisions were leading Britain into “very treacherous waters”.

“Major companies in Europe who have put the UK in their supply chain have been clear,” he told the Observer. “In a competitive world, any kind of movement of goods which would suffer any form of tariff would clearly mean they would have to review very carefully whether they could really afford the cost of those terms.

“In the case of Airbus, it is a very pivotal engineering business in the UK. They have always had to have a wide manufacturing base, but it has always been an irritation to them that manufacturing wings for their aircraft is not carried out in mainland Europe, where its major shareholders are located. I think they feel changing this would be a great Brexit dividend. BMW has said similar things.”

He added: “The truth is that, while ministers say we are going to get a deal, that is not the same as a no-tariff arrangement. We have actually got to have something positive. We cannot wait until next year to know what is going on. The timeline of some of these products is years.”

One senior business figure said further public concerns were on the way and EU countries would benefit from an exodus of UK-based businesses. “There are people waiting in the wings if they think they can intervene without serious consequences from the government,” he said. “The trade that goes overseas probably won’t change the economies of the countries it goes to, but it will add up to a big impact on the UK’s economy.”

Further concerns are due to be voiced by the automotive industry this week, at a gathering of hundreds of industry figures at a conference held by the Society of Motor Manufacturers & Traders.

While there was relief in Downing Street last week that it avoided any defeats on the EU withdrawal bill, senior Tories believe a more serious rebellion is already on the cards over the trade and customs bills, set to return to the Commons early next month.

“Battling about standing orders always felt like a Westminster bubble-type issue – rebelling on trade matters to constituents jobs, as Airbus demonstrates,” one former minister said. Another former frontbencher added: “It is a question of when we pick that argument, not if.”

Meanwhile, senior Brexiters are attempting to push May into a tougher negotiating stance with Brussels. Boris Johnson and other leading cabinet Brexiters have come under renewed attack from business leaders for pushing for a hard Brexit. The foreign secretary, who has been frustrated by the prospect of the UK being tied closely to the bloc, demanded a “full British Brexit” that would allow the country to set its own rules and trade policy.

However, Juergen Maier, the chief executive of Siemens UK, said his interventions were “incredibly unhelpful” and joined calls for a deal that would not hit the flow of trade between the UK and mainland Europe.

A Downing Street source said: “The government is getting on with delivering the Brexit people voted for and we are working hard to ensure that our future outside the European Union is brighter and better.”