Plaid Cymru has ended its pact with the Welsh Government, the so-called "compact to move Wales forward".
It was agreed after the party's leader Leanne Wood challenged Carwyn Jones for the post of First Minister after the 2016 election.
That led to a tied vote in the Assembly and the deal was done to break the political impasse.
The Welsh Government agreed to set up a mechanism to consult Plaid Cymru on key decisions.
Since then, the former Plaid Cymru leader Dafydd Elis-Thomas has left the party and announced that he will vote with Labour, effectively giving the Government a majority. Despite that, UKIP say they're likely to table a motion of no confidence in Carwyn Jones as a result of the new political situation in Cardiff Bay.
Here's the full text of Leanne Wood's letter to party members:
Carwyn Jones responded to the news claiming his conversation with Leanne Wood was 'amicable' and they will 'keep open lines of communication.'
Welsh Conservative leader Andrew RT Davies described the decision as "more chaos from Plaid Cymru":
UKIP's leader in the Assembly, Neil Hamilton, called on Plaid Cymru to join with other opposition parties in a vote of no confidence in the Welsh Government. He repeated a metaphor about the political compact which caused some offence after he used it in the Senedd when the deal was done last year.