THE Tories’ “flawed, damaging and divisive” Trade Union Bill was blocked by the Welsh Assembly yesterday in a vote that could spark a constitutional power struggle in the courts.

The governing Labour Party united with opposition Plaid Cymru and Lib Dem AMs to deny legislative consent to the legislation in Wales by 43 votes to 13.

Public Services Minister Leighton Andrews described the Bill as “punitive, vindictive and breaching the devolution settlement.”

Plaid Cymru leader Leanne Wood added: “The message should be heard clearly today that, on this issue, we stand together and that we carry the majority of this National Assembly with us.”

The veto comes after the Wales TUC published legal advice last week confirming that the Bill does affect devolved public services and therefore requires the consent of the Welsh Assembly.

QC Hefin Rees concluded that Tory ministers would be “acting unconstitutionally” if they sought to impose the Bill without consent.

Yet within minutes of yesterday’s vote, the government in London signalled its intention to do exactly that.

A spokeswoman said: “The Trade Union Bill relates to employment rights, duties and industrial relations, all of which are clearly reserved matters for the UK government under the Welsh devolution settlement.”

The Welsh government can now introduce its own legislation to effectively overturn the Bill.

But that would be open to a legal challenge by Whitehall, opening a dispute that may have to be settled in the Supreme Court.

Judges ruled in favour of the Welsh government in a 2014 case to decide which administration had the power to set agricultural workers’ pay and conditions.

During yesterday’s debate, Welsh Tory leader Andrew RT Davies insisted the debate and decision over the Bill should be made at Westminster.

And he sparked a row by branding the Unite union a “mob” and accusing union officials of “living their political dreams on the back of their members’ subs.”

Labour AMs rounded on the Tory leader, with Joyce Watson accusing him of insulting “the working class of this country” and John Griffiths saying that his “mask has slipped.”

The Welsh Assembly’s vote is the second major defeat for the Bill after Labour, Lib Dem and cross-bench peers united in the Lords last week to defeat the government over changes to party funding.