WHEN William Temple set out to write Christianity and Social Order (1942), his objectives were to vindicate the Church’s right to intervene in economic questions; to show that it has something worthwhile to say; and to indicate clearly where the competence of the Church ended because of the technicalities involved (Comment, 21 July) .

I am acutely aware that, as my colleague Caroline Lucas says often, no one has a monopoly on wisdom. And I am also clear about where I think my own competence ends — indeed, there is a habit of politicians to set themselves up as experts in everything. But, of course, very few, if any, are.

So I want to talk not about knowledge, but about faith. I am a person of faith. And, for me, the Green Party is the natural political expression of my faith — perhaps as the Labour Party was for William Temple in his own day and age.

I am a descendant of the Quaker prison reformer Elizabeth Fry, and I believe that, while Christianity has been responsible for many atrocities and much oppression, it has, can, and should be a force for good.

THIS is a very interesting time for faith and belief in politics. I have never believed in privileging religion: I would like to see bishops removed from the House of Lords, the disestablishment of the Church of England, and an end to the discrimination of religious schools that can select on the basis of faith.

But, equally, I think that the Christian faith has something important to say. And, as someone who longs for the Church of England to be more progressive, I was very pleased to see the Church affirming transgender people last week (News, Comment, 17 November).

But I am also of the view, as G. K. Chesterton said that: “The Christian ideal has not been tried and found wanting. It has been found difficult; and left untried.”

LAMBETH PALACEArchbishop William Temple

The Christian tradition has a wealth of ideas. In the early 1990s, I was working in the House of Commons, and I got a letter from someone called George Dent. He suggested a year of Jubilee in the year 2000, when the debts of the most indebted countries would be written off. I have to confess I nearly fell off my chair laughing. No one was talking about it. No party was signed up to it.

Just a few years later, the G8 were sitting around discussing not whether they could cancel the debts of some of the most indebted nations, but whose debts they would cancel. Whether it be the campaign to abolish the transatlantic slave trade, led by Wilberforce and the Clapham Sect — opposed by some bishops, I might add — or the Christian Socialists of the late 19th century, there are some inspiring figures from history that we can draw on.

BUT let me add one thing. I have been astonished to see the outcry — by some who are clearly bordering on racism — over the Tesco advert that featured a Muslim family. And, similarly, over Greggs for featuring a sausage roll in a crib (News, 17 November).

For me, as a Christian, the things that I get upset about are quite different.

I get angry that this so-called Christian country with a so-called Christian Prime Minister would walk by on the other side of the road when there were refugee children at its border; that it would support a Syrian coalition, with weapons, that is blockading the border in Yemen while tens of thousands of children starve (News, 17 November); and that it would weaponise a welfare state — the safety net that we all rely on — against those who are mentally ill and disabled.

Those are the kinds of things that my Bible teaches me to be offended by.

Jonathan Bartley is co-leader of the Green Party. 

This is an edited extract from the William Temple Foundation Annual Lecture, “Engaging a Politics of Hope — Economics, Belief and the Environment”, which was delivered in London on Wednesday.

williamtemplefoundation.org.uk