LONDON, July 16 (Xinhua) -- British Prime Minister Theresa May insisted Monday night that she had not caved in to the demands of Brexit-supporting politicians when she accepted a string of changes to crucial legislation.

After a noisy and ill-tempered debate lasting around seven hours, May emerged relatively unscathed. But in a crucial vote on her Customs Bill, there was a close shave when she won by just three votes, 305 against 302.

There was a blow for May when a member of her team, defense minister Guto Bebb resigned over the government's acceptance of amendments put forward by Brexit supporter. Earlier Monday a parliamentary private secretary quit her team.

Amendments to a British parliament bill over a future cross-border customs arrangement after Brexit with the European Union were said in the House of Commons to risk wrecking the new trade deal blueprint May set out last week in her white paper.

May said claims that her Brexit plan was now dead in the water were wrong, insisting that the proposed changes submitted by Brexit-supporting Conservatives were consistent with her plans.

As MPs started several days of debates on Brexit legislation measures, Downing Street confirmed it was accepting four amendments. related to the proposed working relationship between Britain and the EU.

One of the amendments would enshrine in law that there would be no customs border down the Irish Sea between the island of Ireland and the British mainland.

The EU has called for a border in the middle of the Irish Sea to avoid the setting up of a hard land border between the Irish Republic and Norther Ireland, which is part of the UK.

In a sometimes heated debate Conservative Anna Soubry said the plan May agreed at her meeting with ministers at her Cheqeurs retreat had now been wrecked by caving in to no-deal Brexiteers.

Soubry described the government's decision to accept the amendments, put forward by European Research Group of Conservative MPs, as complete madness.

"The consequences of this are grave, not just for our country but also for this party," said Soubry.

Labor MP Stephen Kinnock said in the debate: "By capitulating to their proposals she is accepting that the Chequers deal is now dead in the water."

Meanwhile media reports in London said Monday opponents of May in her own Conservative Party are collecting signatures to force a vote of no confidence in her leadership. Some reports claim the number is nearing the 48 required to force a contest.

Media in London speculated Monday night that government managers are planning to introduce measures to bring forward the parliamentary summer recess to this Thursday to avert a leadership challenge, at least until the fall.