As tax avoidance hit the headlines this week, Christian organisations have spoken up about its impact on those living in poverty in the UK and around the world.

Church Action on Poverty, Christian Aid, and the general secretaries of the Methodist Church, the Baptist Union of Great Britain and the United Reformed Church, wrote a joint letter to the Times newspaper speaking out against tax avoidance.

This week, comedian Jimmy Carr came under fire as it was revealed that he has been using an aggressive tax avoidance scheme.

The church groups said that such tax dodging was an injustice that keeps some people poor while others get richer, claiming that in an age of austerity, it is the moral duty of individuals and companies alike to pay their taxes according to both the letter and the spirit of the law.

While Carr apologised for his actions, the church organisations said that this was not good enough.

Joseph Stead, Christian Aid's senior economic justice adviser, said: "Jimmy Carr's apology is welcome, as is his undertaking to avoid such schemes in future. But he is just one man.

"'Christian Aid hopes this will encourage others, including corporations, to look more closely at their tax affairs. We have highlighted for some time the need for much greater responsibility. 

"The Government has a responsibility to close the loopholes that allows this kind of activity to go unchecked, particularly when it allows corporations in rich countries to have such a damaging impact on people's lives in poorer countries. The need is urgent and must be quickly met."

Church Action on Poverty and Christian Aid have teamed up to launch the Tax Justice Bus Tour to call on church members and supporters across Britain and Ireland to join the movement for tax justice – and to call on the prime minister to take action now.