UK and EU flags are seen at the EU council building in Brussels, Belgium, March 29, 2017. (Xinhua/Ye Pingfan)

LONDON, Sept. 14 (Xinhua) -- The negotiations between Britain and the European Union (EU) over Brexit could become a prisoner of the politics of the UK's ruling Conservative Party, according to a leading expert with world's top think tank Chatham House.

As the fourth round of talks between Britain's Brexit negotiator David Davis and EU negotiator Michel Barnier looks set to go ahead on September 25 after a week's postponement, the role of Britain's ruling Conservative Party is likely to be a key input.

"You have a divided Conservative parliamentary party which reflects divided Conservatives across the country -- city Conservatives, business Conservatives versus rural, older Conservatives" said Robin Niblett, director of Chatham House think-tank in central London in a recent interview with Xinhua.

This reflects both a divided country, closely balanced over leave or remain, and a history of division with the Conservative Party that has been a feature of its politics for over 40 years.

"I don't know what is going to happen, the next party conference will be very interesting. The risk in a nutshell is that the Brexit negotiations will again become a prisoner of Conservative Party politics," Niblett said.

Conservatives meet for their conference in Manchester in October, and a weakened prime minister faces a challenge to her power from Cabinet ministers who are strong Brexiters and others who voted for remain and wish to mitigate the possible negative impact of leaving.

PROBLEM FOR CONSERVATIVES

The issue of the EU, or the European Economic Community (EEC) as it was known when the UK first joined it in 1973, has been an ever-present for the Conservatives.

In 1975 the UK had a referendum on EEC entry, and resoundingly voted yes. Traditional party lines of left and right, Labour and Conservative were split, but the leadership and many of the senior members of both parties were in favor of EEC membership.

This included Margaret Thatcher, who later became prime minister. She continued to support the UK in the EU but later turned against it. Her example inspired and gave support to Eurosceptics and an anti-EU tone in British politics.

This led to the foundation of the UK Independence Party (UKIP) with the intention of getting the UK out of Europe.

"The British parliament is now divided over Brexit, the idea was to have a Conservative majority in parliament leading the country into a firm Brexit," Niblett told Xinhua in an exclusive interview.

"May would be leading Britain out of Europe. What you have now is a Conservative Party, the majority of whom voted for remain; remember there has not been a big turnover because they lost seats and did not gain them."

May has a minority in the new parliament and governs with the support of a small party, the Democratic Unionist Party (DUP) from Northern Ireland. The potential for small numbers of MPs to cause trouble if they rebel is great and may prove irresistible.

On one side May faces a tight but small group of determined Eurosceptics. On the other side there are the majority of her MPs, who voted and supported remain.

"So, even though there are only 30 or 40 rebel MPs there are at least half the party in parliament who are sceptical about Brexit and although they accept that it will happen they do not want a silly Brexit. They think No Deal is the worst deal," said Niblett.

TRANSITION DEAL

A year and two months after the Brexit vote it is only now that the Conservative Party has coalesced around a view on how Brexit should be framed -- should it be a complete break or a partial break, a hard or a soft Brexit and should it be a sharp ending at the end of March 2019 or a longer, phased exit.

"Britain when it leaves the EU will have to leave the single market and the customs union because there is no way the UK will ever accept a situation where it is taking rules or having its trade policy determined by other governments," said Niblett.

"That might work for Iceland or some other small country, but Britain is Britain. This is about politics and identity. All this talk about hard and soft is meaningless.

"There is only one type of Brexit. You could talk about transition -- on transitions you can have hard soft and say we reject the authority of the European Court of Justice from the minute Britain leaves the EU but what is rationally happening is that the Cabinet is uniting around a view that there needs to be a two- or three-year period."

Negotiations will determine the details, said Niblett, but areas like farming or air traffic control could exit EU authority at different times.

But a crucial demand of the Brexiters is that Brexit must happen, and Niblett said that for them their demands would be that any transition agreement would result in a full exit, not a halfway house.

"The transition is now accepted," he said. And in that transition it looks like the Cabinet, those who are leave campaigners and those who are remain, seems to have agreed over the summer that a transition will be necessary.

"The strong Brexit people seem to be saying as long as we are leaving and it is crystal clear and binding we have a withdrawal agreement in place by March 2019 we could wait three years for that to become crystal clear."

Niblett said their position was pragmatic; they did not want to be "blamed as the people undermining the British economy they want to be the people who prove that being out of the EU is success."

He added: "They want to give Brexit the best chance possible. I think a majority can live, with a period of continuing European Court of Justice (ECJ) law."

"SENSIBLE" BREXIT

Cameron's gamble on a referendum backfired and cost him his job.

May's gamble on a general election to give her a firmer hand to negotiate and to lead her party also backfired. But she remains prime minister, and Brexit negotiations are set to continue with the aim of the UK having a deal in place by the deadline of the end of March 2019.

Although May's gamble means she lost ground, it does give an opportunity for a broader consensus around what Brexit should look like.

Niblett said: "you have a chance now for a more sensible Brexit; you will have to now have more parliamentary scrutiny of bills. May cannot just push things through saying either you are loyal to this country or you are not. She will have to negotiate as a chairperson, become the mediator in chief and help Britain arrive at a sensible Brexit."

And tantalisingly the Brexit road is not only a complicated one, it is likely to be a long one. Niblett felt that there could be yet another referendum on whatever deal is reached.

"There is a certainly a possibility of a second referendum to approve the deal because I don't think parliament has the authority any more to approve the deal," he said.