* Conservative Party facing “catastrophic split”
* May faces tumultuous party on Sept 30-Oct. 3
* Boris Johnson steps up attacks on May (Adds details)
By Guy Faulconbridge
LONDON, Sept 10 (Reuters) - British Prime Minister Theresa May’s Conservative Party faces a “catastrophic split” if she persists with her proposals on Brexit, which 80 or more of her lawmakers are prepared to vote against, a former junior minister said.
Such public criticism, a day after former foreign minister Boris Johnson cast her Brexit plans as “a suicide vest” wrapped around the British constitution indicates how hard it could be for May to get any Brexit deal approved.
Steve Baker, a former junior Brexit minister who resigned over May’s so-called Chequers proposals on Brexit, told the Press Association he was not advocating a change of leader but warned May faced a massive problem at the Sept. 30-Oct. 3 party conference.
If 80 of May’s 315 lawmakers voted against a Brexit deal based on her proposals the fate of the government and Brexit would depend on the Labour Party because she would not command the 320 votes in the 650-seat parliament necessary.
“If we come out of conference with her hoping to get Chequers through on the back of Labour votes, I think the EU negotiators would probably understand that if that were done, the Tory party would suffer the catastrophic split which thus far we have managed to avoid,” Baker was quoted as saying.
Other Conservatives have given much more modest estimates of the number of lawmakers who oppose her plans. While some Brexiteers are unhappy with her premiership they see May as their best immediate hope of ensuring the UK leaves the EU.
The United Kingdom is due to leave the European Union on March 29, yet little is clear. There is, so far, no full exit deal and it is unclear whether May can push an agreement through the British parliament.
Divisions in the Conservative Party over Britain’s relationship with the EU contributed to the fall of all three previous Conservative premiers - David Cameron, John Major and Margaret Thatcher.
While the EU in recent weeks has given signs it is seeking to ease May into a deal by offering compromises, she is facing an increasingly vociferous group of committed Brexiteers who feel she has been far too weak with the EU.
In an article in the Mail on Sunday newspaper, Johnson pressed his attack on May’s Chequers plan to leave the EU, calling it “a humiliation” that opens “ourselves to perpetual political blackmail”.
May is under fire from all sides of the Brexit debate, with Johnson, favourite to succeed her, leading a push by eurosceptic lawmakers for the government to “chuck Chequers” and pursue a clean break with the bloc.
Baker said May should seek a Free Trade Agreement under the terms placed on the table by European Council president Donald Tusk in March, PA reported.
He said it would be “fanciful” to expect her to secure parliamentary approval for Chequers.
“It is absolutely no pleasure whatsoever to me to acknowledge that, but I look at the mood of colleagues and the mood of the Conservative party in the country and I am gravely concerned for the future of our party,” Baker said.
London and Brussels say they want to get a divorce deal at the Oct. 18 EU Council or at the latest by the end of the year.
Any deal with the EU must be approved by the British parliament, which is due to go on Christmas holiday from Dec. 20 to Jan. 7. If British lawmakers reject a deal in late December or early January, Britain would face the prospect of leaving the EU three months later without an agreement.
Without a deal, the UK would move from seamless trade with the rest of the European Union to customs arrangements set by the World Trade Organization for external states with no preferential deals.
Some business leaders have warned that adding just two minutes onto every lorry’s customs procedure passing through the southern English port of Dover would produce a 14-mile tailback on either side of the Channel after one day.
Supporters of Brexit admit there may be some short-term pain for the UK’s $2.9 trillion economy but long-term it will prosper when cut free from the EU which they cast as a failing German-dominated experiment in European integration. (Editing by Michael Holden and Janet Lawrence)