TORY plans to declare three quarters of public-sector strikes illegal are a threat to the “rule of law,” a top lawyer has claimed.

In an article published by the Morning Star today, Thompsons head of trade union law Richard Arthur slams “tax-avoiding” Tories for being determined to “stifle legitimate opposition to its failed austerity and industrial policies.”

Mr Arthur (left) has joined trade unionists, Labour politicians and other left parties and leading academics in a fight-back against new anti-union laws the Conservatives said they would implement if they won a majority in May’s general election.

Transport secretary Patrick McLoughlin said strikes in “key public services” would be made illegal unless 40 per cent of eligible workers voted in favour.

When the proposals were put forward last week, TUC general secretary Frances O’Grady said they would be “a democratic outrage, especially as the Conservatives have opposed allowing secure and secret online balloting — the one measure guaranteed to increase turnouts.”

Mr Arthur said the Employment Relations Act 2004 already allowed for the implementation of electronic voting — and that the government’s refusal to implement it exposed Tories’ hypocrisy.

“These latest plans aren’t about democratic accountability,” he writes. “They’re about making it impossible for trade unions to organise industrial action in the public sector.

“The reality is that this isn’t just about trade union law, it’s about the rule of the law and the ability of legitimate opponents to coalition policy to mount an effective protest.”