Government refuses to say if it has taken legal advice over new referendum on final EU deal

It comes as the general secretary of the Trades Union Congress said the organisation was 'serving notice' to Theresa May and could throw its weight behind a public vote

Ministers have refused to disclose whether they have taken legal advice on holding a fresh referendum on the final Brexit deal as the government comes under mounting pressure to consider campaigners’ demands.

In response to a request for information, the Department for Exiting the European Union said revealing such detail would harm the UK’s negotiating position in Brussels.

It comes as the general secretary of the Trades Union Congress (TUC) said the organisation was “serving notice” to Theresa May and could throw its weight behind calls for a second public vote in the coming months.

The Independent has also launched its Final Say campaign – demanding a new vote – and more than 790,000 people have signed its petition.

Alongside the People’s Vote campaign, The Independent will lead a protest in central London on 20 October to ramp up calls ahead of the government’s deadline for a Brexit deal with Brussels.

While Theresa May has consistently dismissed such calls, and categorically ruled out a fresh vote, there are increasing demands within her own party and pressure on Jeremy Corbyn to voice his support for the idea.

Asked by Reuters news agency through a freedom of information request what legal advice it had received this year on holding a second referendum, the Brexit department said there was a public interest in refusing to confirm or deny whether it had such information.

“There is a very strong public interest in the most effective pursuance of the UK’s national interests abroad,” the department said.

“It is necessary to consider whether the act of confirming or denying whether we hold information ... would be likely to prejudice the government’s negotiating position, which would be detrimental to the UK’s relationships with other states and with European institutions, and would prejudice the promotion and protection of the UK’s interests abroad.”

The department said it had concluded “the public interest favours maintaining the exclusion” of its duty to reveal whether or not it holds such information.

It gave the same answer to a request for information on whether it had taken legal advice on the reversibility of Article 50, the notice of the intention to leave the EU served by Ms May in March 2017.

In August, a poll for The Independent revealed that public backing for a fresh vote on the Brexit deal had leapt on the previous month by four points.

Asked whether they would support or oppose the idea should a Brexit deal be brokered by the prime minister, 44 per cent of respondents backed a new vote, with 27 per cent opposing, 15 per cent not having strong opinions either way and 14 per cent saying they did not know.

But four weeks later, amid increasing public divisions over Ms May’s Brexit plans, from both inside and outside the Conservatives, 48 per cent said they wanted a second referendum.