(Bloomberg) -- Theresa May has lost a pro-European ally with the resignation of Home Secretary Amber Rudd, the fourth Cabinet member to quit in six months over a scandal, just as internal battles over Brexit come to a head.
The upset destabilizes the U.K. prime minister at a delicate time. Rudd, 54, was due to address lawmakers on Monday to defend herself against allegations that she misled Parliament over targets for deporting illegal immigrants. Now May will need to name a successor while juggling tensions among her top ministers.
Rudd was a key pro-European Union voice who provided a counterpoint to pro-Brexit heavyweights, including Foreign Secretary Boris Johnson and Environment Secretary Michael Gove. She was due to attend a key meeting of the Brexit “war cabinet” on Wednesday to weigh the options for the U.K.’s future trading relationship with the EU.
“Replacing Rudd risks upsetting the Brexit balance in Cabinet,” said Tim Bale, professor of politics at Queen Mary University of London.
Early favorites to succeed her include Environment Secretary Michael Gove, Communities Secretary Sajid Javid and Health Secretary Jeremy Hunt. Also in the mix are Northern Ireland Secretary Karen Bradley and Cabinet Office Minister David Lidington. All except Gove campaigned to remain in the EU.
Rudd’s departure also leaves May “exposed to the full force of the Windrush scandal,” Bale said, referring to the row over the government’s recent treatment of Caribbean migrants who came to the U.K. after World War II.
May’s critics have argued that the hostile immigration policies she introduced when she was home secretary are to blame for the current scandal, with Rudd ultimately paying the price.
Just as Caribbean leaders arrived in London for a summit of former colonies, it emerged that some so-called Windrush migrants -- named for one of the boats they arrived on -- were being refused healthcare, passports and in some cases barred from re-entering the country because they couldn’t prove their citizenship.
The opposition Labour Party wasted no time in turning its fire on May. The prime minister had used Rudd as a “human shield” to protect herself from allegations over the “hostile environment” for immigrants she pursued when she ran the Home Office, the party said.
But it’s over Brexit that May will feel Rudd’s departure the most.
Senior ministers are expected to thrash out this week whether the U.K. stays in a customs union with the EU -- an issue that goes to the heart of what type of Brexit the country will get with less than a year before the country formally quits the bloc in March 2019.
Currency strategists say that removing of a pro-EU Cabinet member could also weigh on the pound, which has fallen more than 1 percent over the past week.
Ministers are at odds over what customs arrangements should replace the current setup, which allows easy trade with Europe through the single market and customs union. Hardline anti-Europeans fear May might water down the terms of Brexit as she struggles to reconcile their demands with those of pro-EU House of Commons lawmakers emboldened by repeated defeats for the government in the House of Lords.
The Sunday Times reported that May has been told to fire the most senior Brexit official in her office, Oliver Robbins, whose proposal for a customs partnership will be discussed on Wednesday. Pro-Brexit ministers hate his plan, and see it as a way of thwarting the kind of divorce they want.
Rudd also incurred the wrath of pro-Brexit Conservatives when she refused to be drawn on whether the U.K. would leave the customs union. “We still have a few discussions to be had in a really positive, consensual, easy way,” she told reporters, her tone heavy with irony.
Though she later tried to undo the damage, it was too late. Conservative lawmaker Peter Bone tweeted: “We cannot have Home Sec not supporting this key plank of Brexit!”
Rudd will be given “a huge welcome” by rank-and-file pro-EU lawmakers, Tory MP Anna Soubry said on Twitter. Vince Cable, leader of the anti-Brexit Liberal Democrats, told the BBC that Rudd, alongside other remainers including Dominic Grieve and Justine Greening, will be “a source of considerable headache to Theresa May and her more Brexit-oriented colleagues.”
Rudd’s exit deprives May of a loyal lieutenant, who filled in for her boss in a televised election debate last year. The prime minister also lost her de facto deputy, Damian Green -- another pro-EU voice -- to a scandal in December. Former Defence Secretary Michael Fallon and former International Development Secretary Priti Patel also left over scandals.
Greening, who resigned in protest in January during a reshuffle where she was asked to move ministries, and former Northern Ireland Secretary James Brokenshire, who quit over ill-health, have also left the government in recent months.
©2018 Bloomberg L.P.