Trade Union Congress general secretary Frances O’Grady issued her starkest warning yet yesterday that a Tory victory in 2015 will see strikes outlawed and wages plummet.

She called for the defeat of the Conservatives at the ballot box and a “fresh start” in a new year’s message reviewing a miserable 12 months for the vast majority of people.

Real-terms average wages fell by another £500 in 2014 — adding to a £2,009 drop since the Tories were elected in 2010, the TUC said.

But Ms O’Grady said that the situation will take a further plunge if Conservative policies continue.

“The average wage is now worth £50 a week less than when this government came to power,” she warned.

“If the Chancellor gets the opportunity to make the deep and rapid cuts he plans for after the election, it will not just damage our social fabric but hinder recovery just as much as his cuts after the last election.”

And a Tory victory would herald a new assault on unions that would “seek to make strikes so difficult that they effectively end the right to strike,” she said.

“If ever implemented this would weaken the union hand in every negotiation, further depressing wages across the economy.”

Warning of a growing economic imbalance under Chancellor George Osborne, she said: “We have become very good at creating low-paid and precarious jobs, but have failed to invest in good, well-paid jobs that make the most of people’s skills and abilities.

“This is why the Chancellor has failed to reduce the deficit.”

Instead she urged a major change of tack, saying even employers see how low wages are hamstringing the economy.

But she added: “We already know enough about the manifestos to see that this will be one contest when no-one can say the parties will all be the same.

“The Autumn Statement opened up a huge choice in British politics between radical cuts and pay freezes versus investment for the future and a strategy for decent jobs, homes and living standards.”