LONDON (Reuters) – British Prime Minister Theresa May’s government suffered a defeat in parliament on Tuesday when MPs who oppose leaving the European Union without an accord won a vote on creating a new obstacle to a no-deal Brexit.

The 303 to 297 defeat means that the government needs explicit parliamentary approval to leave the EU without a deal before it can use certain powers relating to taxation law. May’s office had earlier played down the technical impact of defeat.

The defeat highlights May’s weak position as leader of a minority government, a divided party, and a critical parliament just days before she is due to hold a pivotal vote on whether to approve the Brexit deal she has negotiated with the EU.

“This vote is an important step to prevent a no-deal Brexit. It shows that there is no majority in Parliament, the Cabinet or the country for crashing out of the EU without an agreement,” opposition leader Jeremy Corbyn said.

Speaking before the vote, Treasury minister Robert Jenrick said the proposal’s only impact would be to make the country “somewhat less prepared” for a no-deal outcome.

With less than three months until Britain leaves the EU, May is struggling to win approval for her Brexit deal.

A no-deal exit is the default scenario if May’s deal is rejected, and the prospect of possible supply chain disruption, medicine shortage and blocked ports has in recent weeks pushed companies and the government to ramp up contingency planning.