Minister Hazel Blears has said she, not David Blunkett, is in charge at the Home Office while home secretary Charles Clarke is away on holiday.
Hazel Blears is starting talks with Muslim leaders
Reports in Sunday newspapers suggested ex-Home Secretary Mr Blunkett was filling in during Mr Clarke's absence.
But Ms Blears told BBC News: "It is absolutely clear that in the absence of the home secretary, I am responsible for matters in the Home Office."
Asked if she was the boss, Ms Blears laughed and replied: "Indeed."
Mr Clarke delayed his planned holiday but faced criticism in the media for leaving the UK last week while the hunt for the London bombers continued.
He was defended by Prime Minister Tony Blair, who said Mr Clarke was entitled to a break but could return quickly if he was needed.
Ms Blears, who is minister for policing, security and community safety, is on Tuesday starting a series of talks with Muslim leaders and police in the wake of the London bombings.