A Liberal democrat Cabinet minister stoked up Coalition tensions as he ridiculed calls from the Tory right to scrap the 50p top rate of income tax for the highest earners as "cloud cuckoo land".
Danny Alexander, Chief Secretary to the Treasury, was scathing about a suggestion that cutting taxes for the best-off would make the economy more competitive.
The step was advocated yesterday by two former Tory Cabinet ministers. Lord Norman Lamont said tax rates were "uncompetitive", while Lord Tebbit said: "The 50% rate of income tax could go - it raises no revenue."
Last week, Mayor of London Boris Johnson backed the move as "a signal that London is open for business".
Mr Alexander said: "Anyone who thinks we are going to shift our priority to reducing the tax burden for the wealthiest has another think coming. That cannot be the right priority."
"The idea that we are going to somehow shift our focus to the wealthiest in the country at a time when everyone is under pressure is just in cloud cuckoo land," he added.