Tens of thousands of people have marched through London on the second anniversary of the EU referendum to demand a fresh vote on the terms of the Brexit deal.

Politicians from across the political spectrum took part in the People’s Vote rally on Saturday as the divisions over withdrawal from the European Union showed no sign of narrowing.

Lib Dem leader Sir Vince Cable and his predecessor Sir Nick Clegg, Green co-leader Caroline Lucas, actor and Labour activist Tony Robinson and pro-EU campaigner Gina Miller were among those who joined the crowd in the capital.

The demonstration came after leading Brexiteers warned that Britain is prepared to walk away from negotiations without a deal.

Boris Johnson urged the Prime Minister to deliver a “full British Brexit”, saying people would not tolerate a “bog roll Brexit” that was “soft, yielding and seemingly infinitely long”.

International Trade Secretary Liam Fox told the BBC the UK was not “bluffing” about quitting Brussels talks and Brexit Secretary David Davis said in an interview with the Express there is “lots going on” to prepare in case negotiations collapse.

People’s Vote march
Crowds gather on Pall Mall in central London (John Stillwell/PA)

Their remarks were published on Saturday but made before Airbus on Thursday threatened to quit the UK in the wake of a no-deal Brexit.

The head of Siemens UK criticised the politicians, saying their comments were “incredibly unhelpful” and said it was time to work for a more pragmatic deal with the EU.

Juergen Maier told BBC Radio 4’s Today that the firm wanted a soft Brexit with “minimum friction”, saying the Government had presided over “two years of not having achieved what we were promised, which is that this was all going to be easy”.

He said: “I think the realities are setting in and I think it is time to get away from slogans, ‘full British Brexit’, ‘going into combat with Europe’.

“It’s all incredibly unhelpful and what we need to do now is to get closer with our European partners and work out what a realistic, pragmatic Brexit is that works for both sides, the EU and ourselves.”

POLITICS Brexit Airbus
(PA Graphics)

A large crowd waving EU flags and placards attended the People’s Vote rally on Saturday afternoon, walking from Pall Mall to Parliament Square.

The People’s Vote estimated that 100,000 took part, but the figure could not be independently verified.

Sir Vince told the Press Association he thought evidence was pointing towards a public rethink of Brexit if the terms of any deal were put to a vote.

He said: “There are lots of things we didn’t know at the time. We didn’t know about the cost of the divorce bill, about the fact that we’d have less not more revenue for the NHS, we didn’t know about the Irish frontier problem.

“We didn’t know that we’re going to get president Trump or we’re going to destroy the trading system on which Brexit depends. The mood has changed.”

Labour campaigned in support of Remain in 2016 and there were chants of “Where’s Jeremy Corbyn?” from the crowd.

The opposition leader is in Jordan visiting refugee camps and the party does not officially support a second referendum

Shadow chancellor John McDonnell said he would prefer a general election to a second referendum if a Brexit deal cannot be agreed and approved before the UK leaves the EU.

Addressing the conference of the grassroots Open Labour group in London, the MP, whose Hayes and Harlington constituency in West London voted Leave, said he wanted to avoid a Ukip resurgence or a repeat of xenophobia that marred the 2016 vote.

Meanwhile, research by the Centre for European Reform (CER) think tank indicated Brexit had already made the UK economy 2.1% weaker than it would have been if voters had decided to stay in the EU.

The CER estimate is equivalent to a knock-on hit of £23 billion a year to the public finances, some £440 million a week.

CER deputy director John Springford said: “Two years on from the referendum, we now know that the Brexit vote has seriously damaged the economy.”

Dr Fox told the BBC it is “essential” the EU “understands… and believes” the Prime Minister’s assertion that no deal would be better than a bad deal.

He said the threat had “added credibility because if we were to leave, the economic impact on a number of European countries would be severe”.

“I think our negotiating partners would not be wise if they believed that the Prime Minister was bluffing,” he said.

Speaking to the Daily Express, Mr Davis said that Britain was “able to leave without a deal”.

“We don’t want to do that, never have. The best option is leaving with a good deal but you’ve got to be able to walk away from the table,” he said.