Gordon Brown's troubles have deepened amid reports that three more ministerial aides have raised concerns over the abolition of the 10p income tax rate.
Jeff Ennis, aide to Cabinet Office Minister Ed Miliband - one of Mr Brown's closest allies - said "everybody has concerns" over the decision to scrap the lower tax rate, which experts claim will leave up to five million households worse off.
The normally loyal Mr Ennis ruled out voting against the Government over the issue or resigning from his Parliamentary Private Secretary (PPS) post, but called for targeted support to help those affected by the decision.
Dave Anderson, PPS to Higher Education Minister Bill Rammell, and Celia Barlow, aide to Science Minister Ian Pearson, are also reported to have voiced concerns about the issue.
Mr Ennis, MP for Barnsley East and Mexborough, said: "I think everybody has concerns about it. But the die is cast already, so I will be supporting the Government, but hoping the issue of the 10p rate removal will be redressed with targeted support in the near future."
On Thursday night, the Prime Minister was forced to interrupt his official visit to the US to speak to Angela Smith, parliamentary aide to Treasury Chief Secretary Yvette Cooper, by telephone from The White House after she reportedly told colleagues she was set to quit.
Ms Smith, MP for Sheffield Hillsborough, is understood to have discussed her misgivings with senior ministers, government chief whip Geoff Hoon and the PM before issuing a statement admitting she had "concerns" about the tax move but would stay on.
"It is true I have concerns over tax changes and these have been discussed with senior government figures," she said.
"I am reassured that my concerns are understood and that the Government remains committed to its anti-poverty agenda. Resignation of my post is therefore not envisaged."
