His attack came after he questioned the Brexit Minister over claims that EU elections will in effect be a second referendum.
Addressing the Counsel General and Brexit Minister Jeremy Miles AM in the Assembly Chamber, Mr Isherwood (pictured) said: “Last week, Labour's ruling body rejected calls for the Party to commit to a second EU referendum, with some senior Labour figures counselling that the alternative would have forfeited leave-supporting Labour areas, but with others having since quit the Labour Party because of Mr Corbyn's failure to support a second referendum - a situation, may I say, that other Parties may be familiar with also.
“How, therefore, do you respond to those who are saying that the EU elections, which we now know are going ahead on 23 May, will in effect be a second referendum?”
In response, the Minister said: “We will be engaging in these elections, reminding people of the benefits that membership of the European Union has had for Wales. I think the lesson for us here is that we should all, in this place, recognise the value that Wales has derived from membership of the European Union. I think any relationship with the European Union short of that is less good for Wales than membership. I think we will take the opportunity, in the coming weeks, of reminding people of the advantages that we have had as members of the European Union.”
Mr Isherwood added: “Although some 60 per cent of UK Labour constituencies voted to leave, including 59 per cent in Wrexham and 56 per cent in Flintshire, and although the Labour Welsh Government claims to respect the outcome of the referendum, Labour Welsh Government Ministers never cease in their campaign to undermine it. At least Plaid Cymru are honest about their intention to betray the result of the EU referendum, despite Wales voting to leave the EU."