LONDON—One of British Prime Minister Theresa May’s most trusted lawmakers said on Nov. 27 he will not back her Brexit deal, further stacking the odds against it passing through parliament next month.
Under the deal secured with EU leaders on Nov. 25, Britain would leave the bloc in March with continued close trade ties. But the agreement has attracted criticism from lawmakers of all parties, both from supporters of a cleaner break with the EU and from opponents of Brexit.