Ms Smith, Parliamentary Private Secretary to Treasury Minister Yvette Cooper, had reportedly told colleagues she intended to quit over the controversial tax move.

But a senior Treasury aide said: "Angela Smith had concerns about the impact of the tax changes.

"She raised those concerns with senior ministers, but that is the end of the matter.

"She is not resigning from her role as Parliamentary Private Secretary."

He added: "As the Prime Minister has said in Washington, we will at every stage do all we can to support pensioners, families and people on low incomes."