LONDON - Theresa May will press on with efforts to secure a revised Brexit deal, despite another Commons defeat, and will return to Brussels "within days".
MPs voted against a motion endorsing the government's strategy by 303 to 258, with 66 Tory MPs abstaining.
Steve Baker, of the Conservative backbench European Research Group, which led the rebellion, called the loss a "storm in a teacup".
Business Minister Richard Harrington accused the ERG of "treachery".
Mrs May is trying to renegotiate the Irish backstop with the EU after MPs voted to replace it with "alternative arrangements" earlier this month.
Some MPs fear that the backstop - the insurance policy to prevent the return of customs checks on the Irish border - will see the UK will be bound to EU customs rules in the long-term.
The government motion on Thursday called for MPs to back its existing strategy, including seeking changes to the backstop, but ERG members believed voting for it would also see them endorsing calls to rule out a no-deal Brexit.
They say the option of leaving the EU without a formal deal is essential as "negotiating leverage" in Brussels, but a majority of MPs believe it would cause chaos at ports and massive disruption to business.
The EU has repeatedly rejected the idea of changing the backstop in the withdrawal agreement.(FA)