LONDON (Reuters) - If Brexit talks break down without a deal, half of Britons believe the final decision over whether to leave the European Union should be taken by the public in a referendum, according to a survey of more than 10,000 people published on Friday.

Anti-Brexit demonstrators wave EU and Union flags opposite the Houses of Parliament, in London, Britain, June 19, 2018. REUTERS/Henry Nicholls

The YouGov poll, conducted July 31-Aug. 7 and commissioned by the pro-referendum “People’s Vote” campaign, found 45 percent of voters supported holding a new referendum whatever the outcome of talks with the EU, while 34 percent opposed it.

If negotiations with the EU fail to produce a trade deal, 50 percent said the public should vote on whether to leave the bloc anyway, while 25 percent said lawmakers should decide by voting in parliament.

“Across the spectrum, the message from voters in this survey is clear: if the government and parliament can’t sort out Brexit, the people should,” said Peter Kellner, a former president of YouGov.

With less than eight months until Britain is due to leave the EU, Prime Minister Theresa May has yet to find a plan for future ties that pleases both sides of her divided party and is acceptable to negotiators in Brussels.

She has proposed a compromise that would keep Britain in a free trade zone with the EU for manufactured and agricultural goods, which would still have to comply with some EU rules. Some in her party want closer ties; others favour a cleaner break.

Chancellor Philip Hammond, known as a supporter of close EU ties, said on Friday that under May’s proposal he expected the economy would “grow at broadly the rate that it would have done had we remained in the European Union”. The treasury has previously forecast that other scenarios, all involving a cleaner break, would harm growth.

“The chances are that we will get a trade deal, I expect that to be the outcome but I recognise that there is a possibility that it doesn’t happen,” Hammond told reporters during a visit to central England.

UNPOPULAR

The YouGov poll showed May’s proposal has yet to win popular support with either side. Faced with a three-way choice between remaining in the EU, leaving with no deal or accepting May’s proposal, 40 percent favoured remaining, 27 percent wanted to leave without a deal and just 11 percent favoured the deal.

London and Brussels seek a final deal in October to give time to ratify it. At the weekend British trade minister Liam Fox said he saw a 60 percent chance of a “no-deal” Brexit, which would see the world’s fifth-largest economy quit the EU on March 29, 2019 without a trade agreement.

Sterling slid to its lowest level in more than a year on Friday, bringing its loss since Monday to 1.9 percent, on concerns Britain could leave the EU without a deal.

May has repeatedly ruled out another public vote on Brexit, saying the public spoke at a June 2016 referendum, when 51.9 percent backed leaving and 48.1 percent wanted to stay.

Goldman Sachs said it believed May would clinch a deal on access to EU markets for goods and get it passed by parliament, though a disorderly exit remained possible.

The YouGov poll found 74 percent of those questioned believed the negotiations were going badly, and 68 percent thought that made it likely Britain would get a bad deal.