LONDON (Reuters) - Pro-EU campaigners have set out how parliament could force the British government to call a fresh vote on Brexit, arguing that there is still time for another referendum.

Pro-EU demonstrators protest outside parliament in Westminster London, Britain, September 13, 2018. REUTERS/Henry Nicholls

Britain’s narrow 2016 vote to exit the EU still divides public opinion with less than seven months until the country is due to leave the bloc. Prime Minister Theresa May is struggling to win support at home and in Brussels for her exit plan.

May has rejected the idea of a second referendum on leaving the EU, but the campaign for a so-called “People’s Vote” on whether to accept any deal that May is able to agree, has won support from some in parliament.

In a report co-authored by the man who drafted the EU treaty clause Britain is using to exit the bloc, the People’s Vote campaign said parliament would have a series of opportunities to encourage or force the government to hold a referendum.

“The die is not irrevocably cast, there is still time,” said John Kerr, who wrote the Article 50 exit clause of the EU’s Lisbon Treaty that May used in March 2017 to set a two-year countdown running on Britain’s departure.

The campaign cited polling data from YouGov showing more people would back a second vote than oppose one. Most opinion polls show a slight shift away from voting for Brexit, but overall opinion remains basically split down the middle.

The report set out six scenarios under which parliament could fight the government - ranging from technical procedures that would turn a planned vote in parliament on approving her deal into a one calling for a public vote, to the collapse of her government and a new election.

All rely to some extent on May, who does not have an outright majority in parliament, failing to win over skeptical lawmakers within her own party.

“The combination of parliament having meaningful votes, together with the government’s lack of a reliable majority, means that MPs (Members of Parliament) will play a central role in scrutinizing any deal and could yet reject it,” the report said.

The government has agreed to let lawmakers vote on whether to accept any deal May is able to negotiate with Brussels. But her negotiating plan is unpopular within her divided party, and it is not clear that she will be able to win a vote on it.

Nevertheless, May said that if her deal is rejected by parliament, Britain will leave the bloc without any deal - an outcome that many economists, including the International Monetary Fund, say would damage the economy.

Some pro-Brexit lawmakers argue that the dangers of leaving without a deal are being hyped up to generate fear, while both May’s government and the EU have published no-deal contingency plans to try to mitigate any impact.