Trade Union Bill advice 'embarrassing' to UK government
The UK government has been urged to drop plans to restrict public sector strikes in Wales, after a leaked letter suggested ministers accept they have a "very weak case" to impose the measure.
Labour has argued that the Trade Union Bill should not apply to devolved services such as health and education.
Welsh Public Services Minister Leighton Andrews said the leaked legal advice was "embarrassing".
The UK government said it did not comment on leaks.
New rules for industrial action would mean strikes affecting key public services are allowed only if backed by 40% of those eligible to vote.
But opponents in Wales and Scotland have argued that the UK government cannot impose such measures on public services which are devolved.
First Minister Carwyn Jones has threatened to defy Westminster by passing Welsh laws on strikes even if it results in another Supreme Court battle over where responsibility lies.
As the House of Lords prepared to discuss the bill on Monday, a leaked letter marked "sensitive" emerged, signed by Skills Minister Nick Boles.
It indicated that legal advice suggested that while the measures would apply to Scotland as a matter reserved to Westminster, there was a "very weak case" where Wales was concerned.
The letter added that some concessions could be made to "take some of the heat out of the DAs' [devolved administrations] opposition to the Bill".
Mr Andrews said: "This is embarrassing for the Tory government.
"Their own legal advice confirms what we already know, that they have a very weak case for legislating in this area.
"The Bill as it stands is a clear breach of the devolution settlement.
"We repeat our call for the UK government to drop the clauses relating to public services that are the responsibilities of devolved administrations."
Plaid Cymru MP Jonathan Edwards said: "The legal case for implementing the Trade Union Bill in Wales is evaporating, and the moral case never existed."
A UK government spokesman said it was "committed to implementing the Trade Union Bill to fairly balance the right to strike with the rights of millions of people to go about their daily lives".
'Waging a war'
Earlier, Baroness Morgan of Ely, a Labour peer, called for changes to the bill to limit its impact on Wales.
"While the Tories seem intent on waging a war against hardworking doctors, teachers and firefighters, in Wales we have a Welsh Labour government that respects and values our public services and works with them, not against them," she said.
"The UK government would be acting with high handed arrogance if it continued to pursue this path of imposing the Trade Union Bill on public service provision in Wales, and it is highly likely that they would be acting unconstitutionally."