THERESA May has suffered another defeat on her key Brexit legislation after members of the House of Lords voted to keep the EU rights charter in domestic law.

Peers voted by 316 votes to 245 – a majority of 71 – to keep most of the EU charter of fundamental rights in UK law. The vote follows two other defeats for the UK Government last week in the Lords on the EU Withdrawal Bill, which transfers EU law into UK law after withdrawal from the bloc.

Calling for the majority of the charter to be retained after Brexit, leading lawyer and cross-bencher Lord Pannick warned that exclusion of its rights for the child, the elderly and the disabled, among others, was “unprincipled and unjustified”.

He said to exclude a number of important EU rights from domestic law would lead to a lack of certainty and continuity, providing a “recipe for confusion” after Brexit.

“I fear the government is seeking to make an exception for rights under the charter because the government is suspicious of the very concept of fundamental rights,” Pannick told peers.

Accusing ministers of acting for purely “doctrinal” reasons, he said: “This Bill should not be used as an excuse to reduce the legal rights which we all enjoy against the state.”

Labour peer Lord Cashman, co-founder of the charity Stonewall, urged peers to support the charter, saying a repetition of a right did not weaken it.

Cashman said: “This country has never been more divided and more hostile to the opinions of others. Discrimination and victimisation are not diminishing, they are on the increase.

“We face great challenges and unprecedented change, and therefore I would argue that we need more certainty, more reassurance, not less.”

Crossbencher Baroness Deech said retaining the charter could be a “bonanza” for litigation lawyers and that it had failed to protect human rights in other European countries.

“The retention of the charter would be a Trojan horse with a tapeworm in its intestines, because its interpretation would depend on the ongoing, never-ending, twisting and turning judgments of the ECJ,” she said.

“A vote for these amendments, to keep the charter, is tantamount to a vote of no confidence in the ability of our judges and this Parliament to make and interpret the law.”

Meanwhile, tensions in the Cabinet have intensified with May facing calls from Brexit-supporting ministers to ditch any plan for a customs deal with the EU following their concerns she is prepared to strike a compromise arrangement.

David Davis, Liam Fox and Boris Johnson are to press the Prime Minister to abandon any softening of her stance which emerged following reports last week that Brussels rejected the UK’s Irish border plans.

The ministers believe that the so-called customs partnership put forward by May is unworkable and is encouraging Brussels to press for Britain to stay in a customs union after Brexit.

Reports over the weekend suggested Johnson may resign if May seeks a compromise on the customs union issue.

Yesterday Downing Street insisted the government’s position on leaving the customs union would not change.

“We will not be staying in the customs union or joining a customs union,” a source told the BBC.

Friction has increased sharply in the Cabinet after a heavy defeat for the government in the Lords last week with peers voting in favour of a customs union and the prospect of a Commons vote on Thursday urging ministers to remain within a customs union. That vote is non-binding but legislation due to return to the Commons this summer will provide an opportunity for Tory rebels who back Remain to join other opposition parties to force a climbdown.

Reports on Saturday said Downing Street had been warned that May would face a leadership challenge if she abandoned her stance that Britain would not be in a customs union after Brexit.