By Tony Hudson
George Osborne's Budget proposals on tax avoidance are being dismissed as a "sham" by campaigners.
The chancellor is expected to put forward a general anti-abuse rule in his statement this afternoon, but the proposal is already under fire for making the problem of tax avoidance worse.
Anti-poverty charity War on Want claims the rule defines tax avoidance so narrowly it would actually widen expectations of what is acceptable behaviour for corporations.
"Osborne's attempts to tackle tax avoidance are little more than a sham," said Murray Worthy, a tax campaigner for the charity.
"The public are outraged that, for big companies like Starbucks, paying tax seems to be little more than a matter of choice."
Worthy went on to slam Osborne for going easy on large corporations while continuing with extreme spending cuts, calling it "an outrageous injustice".
Last week, the government was criticised by Lord MacGregor, chair of the Lords committee which scrutinises the Budget, for unrealistically portraying the expected impact the GAAR would have.
"There is a misconception that GAAR will mean the likes of Starbucks and Amazon will be slapped with massive tax bills. This is wrong and the government need to explain that to the public," he said.
Lord MacGregor is not the only peer critical of the government's approach to curtailing tax avoidance.
Writing for politics.co.uk, Lord Collins welcomed the government's intention but said "so far, any real action on the issue has fallen far short of a real crackdown". He called on the coalition "to move from rhetoric to deeds".
"The rhetoric of what the prime minister and the chancellor is now saying is good, but they need to follow it through with concrete action in the Budget to end tax secrecy," he added.