The Green Party is not going to contest the Brecon and Radnorshire By-election is has confirmed, in a move which is expected to boost the Liberal Democrats.
It said it has taken the decision as "current government policies, including the threat of crashing out of the EU, are bad news for people and environment".
Wales Green Party leader Anthony Slaughter said: "The local Green Party in Brecon and Radnor has chosen not to contest the upcoming by-election, in order to maximise the chances of the candidate most likely to beat the Conservatives and the Brexit Party.
"Our local Green Party, like some other parties, has decided in these very particular circumstances that the best choice right now is to put Wales before tribal politics. We will always stand up for environmental and social justice, but current government policies, including the threat of crashing out of the EU, are bad news for people and environment."
Meanwhile Plaid Cymru has said it is continuing to talk to other "pro-remain" parties.
A spokesman said: “After the European election, in which Plaid Cymru was returned as Wales’ leading pro-remain party, our leader Adam Price wrote to the leaders of other pro-remain parties seeking co-operation.
“He did that because it is clear that Brexit is not the settled will of the people, despite what the Tory leadership candidates would have you believe.
“To that end, conversations with other pro-Remain parties are continuing.”
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