Former health minister Jane Kennedy has revealed that she resigned from the government because she feared NHS reform was going too fast.
The Liverpool MP left the Labour frontbench voluntarily on Thursday, it emerged over the weekend.
She said she had raised her concerns within the Department of Health but had been told to keep quiet by colleagues.
"For some time I have had disagreements with the way in which certain aspects of health reforms were being dealt with, and it obviously led to some disputes with fellow ministers and some at Number 10," she told the Observer.
"I had been asked to do a job and bring political judgment to the job.
"When you try to apply that judgment and you are told you shouldn't be expressing your opinions you realise the government needs to get somebody else."
Kennedy's constituency includes Alder Hey hospital, which has warned that the new payment-by-results system could damage their ability to provide treatment.
She said she had struggled with the "uncomfortable question" about why it was being implemented before hospitals were ready.
