EU referendum: Plaid Cymru leader Leanne Wood warns of constitutional 'crisis' if English voters engineer 'Brexit'

Ms Wood backed Nicola Sturgeon's call for UK to only leave the EU if voters from all four nations support it

Leanne Wood has backed the SNP leader Nicola Sturgeon’s call for “Brexit” only to take place if it is supported by voters in each of the UK’s four nations (Reuters)

Plaid Cymru’s leader has warned of a constitutional “crisis” if English voters were to railroad the rest of the United Kingdom into leaving the European Union in the membership referendum promised by David Cameron.

Leanne Wood told the Independent: “It remains to be seen how people in Wales would take it. It would create a serious crisis in terms of the constitution.”

Speaking ahead of Plaid’s annual conference, she backed the SNP leader Nicola Sturgeon’s call for “Brexit” only to take place if it is supported by voters in each of the UK’s four nations.

Ms Wood also said the uncertainty over membership of the EU was already affecting business confidence in Wales.

She is seeking to rally activists’ spirits following a disappointing general election performance in which Plaid only achieved a marginal increase in its vote share. She will also use the conference in Aberystwyth to launch her party’s campaign for next year’s elections to the Welsh Assembly.

“We are expecting to do better in next May’s elections but how we do is largely down to how our supporters work between now and then,” she said.

Plaid is putting health at the top of its policy priorities during the campaign, accusing the Labour, who have been in power since the Assembly's creation 17 years ago, of failing to deliver on promises to improve hospital standards in Wales.

She said: “Labour have become very good at describing the problems in our NHS, and its problems in the future, but people now deserve a party that’s ready to face the challenges we face and make the birthplace of the NHS a beacon for health care.”

Ms Wood added: “Our nation has all the ingredients to be a success story and Plaid Cymru is ready now to provide the leadership that Wales now needs.”