Education Secretary Ruth Kelly has defended her role in the Catholic conservative movement Opus Dei.
Ms Kelly says that her faith is a private matter
Ms Kelly insisted in an interview with the Daily Mirror that her faith was a private matter which had nothing to do with her job.
Opus Dei, which means "Work of God" in Latin, adheres strictly to the teachings of the Catholic Church.
Critics accuse the religious organisation of being secretive and elitist but members reject this.
They prefer to regard it as discreet.
The education secretary, who at 36 is the youngest woman to be appointed to the Cabinet, said of her involvement in the organisation: "I don't see why it should be an issue at all.
"I am in politics because I have a strong belief in the equal worth of every child," Ms Kelly said.
"I have a private spiritual life and I have a faith. It is a private spiritual life and I don't think it is relevant to my job. I am here as a Catholic."
Ms Kelly has attended meetings of Opus Dei but has not revealed whether she was a member.
She rejected a suggestion that her religious beliefs could affect the way she carries out her role in government in relation to sex education.
"We have an established government policy on that. I came here to do a job which is about raising standards in schools," she insisted.
The Opus Dei organisation is relatively small with membership estimated by some at around 80,000 in 80 countries worldwide.
It is founded on the principle that ordinary Catholics can achieve holiness in their everyday lives.
Some members of the movement practise "self mortification" including fasting and flagellation as a way of reminding themselves of how Christ suffered.