British Prime Minister David Cameron was forced into a hasty cabinet reshuffle on Saturday as the dramatic resignation of a senior minister threatened to widen divisions over Europe within the ruling Conservative party.
The rancorous departure of Work and Pensions Secretary Iain Duncan Smith, a leading campaigner for Britain to quit the European Union, also deals a blow to the political ambitions of Chancellor George Osborne, commentators said.
Cameron and Osborne are both urging Britons to vote to remain in the EU in a June 23 referendum but many Conservative members of parliament and activists favour a "Brexit". The issue has riven the party for decades.
In his resignation letter on Friday, Duncan Smith, a former Conservative party leader, cited cuts to disability benefits outlined in Osborne's annual budget last week, which also included tax cuts for richer households. He complained about pressure from the Treasury to cut welfare payments in order to meet fiscal conditions set out by Osborne.
"I am unable to watch passively whilst certain policies are enacted in order to meet the fiscal self-imposed restraints that I believe are more and more perceived as distinctly political rather than in the national economic interest," he wrote.