Tax-dodgers will be given an easy ride by their Tory chums in new rules meant to clamp down on abuse, the TUC warned yesterday.

The government's General Anti-Abuse Rule (GAAR) is so poorly designed that it will allow 99 per cent of tax avoidance to continue.

According to Treasury estimates, the rule will raise £40-£60 million a year - just 0.2 per cent of the estimated £25 billion lost to tax cheats every year.

The TUC warned that loopholes are so narrowly defined under the GAAR that it would not have affected any of the big tax scandals uncovered in the last year - including those infamously exploited by Google, Amazon, Starbucks and Npower.

It urged ministers to include better measures in this week's Autumn Statement to plug the hole tax-dodgers have punched in the Treasury's coffers.

General secretary Frances O'Grady said: "What was once a laudable plan has been hijacked by the tax industry and turned into a damp squib.

"The government itself admits that the rule will only claim back around £50m a year - a mere drop in the ocean.

"The Chancellor has the perfect opportunity this week to announce a proper crackdown on tax dodging.

"He should beef-up the anti-abuse rule so that it closes down loopholes and raises billions, not millions, for ordinary taxpayers who have no choice but to pay the level of tax the government says they should."

The Tax Justice Network campaign group also slammed the initiative, calling it a "wasted opportunity" to stop abuse.

"The impression we have is that it has a very narrow range of focus and has very little purpose as a deterrent," director John Christensen said.

"We are concerned that it just legitimises the abuses it does not cover."

Criticism of the GAAR has focused on a "double reasonableness" test, which states that a tax loophole is fine unless it "cannot reasonably be regarded as a reasonable course of action."

The TUC says this effectively gives a free pass to all tax-dodging schemes.

Another sticking point is that any new anti-avoidance rules have to be agreed by a panel of experts drawn from tax firms or the tax departments of businesses - the very people the TUC say are likely to take advantage of the loopholes the panel is supposed to be closing down.

And there are no penalties for using a loophole that is under investigation.

This means that there is no disincentive for tax cheats to squeeze such dodges dry.

Chancellor George Osborne plans to use the paltry amount brought in to hand out £1,000 grants for households to pay for insulation and other energy efficiency measures.