Scotland's First Minister Nicola Sturgeon makes a statement to the Scottish Parliament in Edinburgh, Scotland, Britain January 8, 2019. REUTERS/Russell Cheyne

EDINBURGH (Reuters) - Scotland’s parliament and the Welsh national assembly voted on Tuesday to oppose the Brexit deal agreed by the UK government, the first time they have done so simultaneously in a sign of the United Kingdom’s internal fracture over Brexit.

Britain’s 52-48 percent 2016 vote to leave the EU has stretched relations between the four-nation United Kingdom because England and Wales voted to leave but a majority in Scotland and Northern Ireland voted to stay.

Since then, both the Scottish and the Welsh devolved governments say their voice has been ignored in British Prime Minister Theresa May’s plans to take Britain out of the EU, something London denies. They are worried about its economic impact and the vote on Tuesday, despite having no binding effect, is a way of formalizing their political opposition.

May herself is struggling to come up with changes to a Brexit deal which could unite a fragmented national parliament at Westminster before the March 29 EU exit deadline.

“The prime minister’s deal will cause major, lasting damage to jobs, living standards and public services such as the National Health Service and should be voted down,” said Scotland’s constitutional relations minister Michael Russell.

“The UK government must also stop using the threat of a catastrophic “no deal” outcome to blackmail the UK parliament into accepting her deeply damaging plans,” he said.

Political decision-making in Britain is heavily devolved, although the Westminster parliament in London is sovereign and has the final say over Brexit.