Church of England bishops have come under fire from Conservative MPs after issuing a plea for Christians to engage with politics in the run-up to the general election.

A pastoral letter to be sent by the House of Bishops to every parish calls for a 'fresh moral vision of the kind of country we want to be', and attempts to counter the 'don't vote' message of comedian Russell Brand by stating it is the 'duty' of every Christian adult to vote.

But Tory backbenchers accused the bishops of offering a prescription with a 'very definite left-wing leaning', while David Cameron urged the Church to recognise the value of work creating a better society and the dangers of a welfare system that pays people to stay idle.

The Bishop of Norwich, the Rt Rev Graham James, insisted that the 52-page letter was not a 'shopping list of policies we would like to see', but 'an encouragement to our own people to be engaged with our political culture'.

Asked about accusations that the letter resembled a list of SNP or Green Party policies, he told BBC Radio 4's World At One: 'I don't believe that – I think it's much more even-handed than that. The only manifesto the Church is signed up to is the teaching of Jesus.'

The letter warned of 'worrying and unfamiliar trends' which have seen 'a growing appetite to exploit grievances, find scapegoats and create barriers between people and nations'.

It argued that there was a 'deep contradiction' between Britain's avowed commitment to equality and the way in which the poor and vulnerable are sometimes treated as 'unwanted, unvalued and unnoticed'.

The Pastoral Letter's introductory statement by the Bishop of Norwich

We have known the date of the next General Election, May 7, for a long time as a result of the Fixed Term Parliaments Act.

In this context the House of Bishops has had an opportunity to reflect on some of the social, political and spiritual challenges facing our nation today.

This Pastoral Letter is addressed to members of the Church of England. It does not indicate preference for any single political party or programme. It encourages Christians to engage positively in our political processes, to use their vote and to value hard won democratic freedoms.

More specifically, it reminds Anglicans of some important features of Christian belief, namely that God's creation is good, that human beings are made in God's image and likeness, that Jesus Christ came to live alongside us, and that we are called to follow His teaching to love one another as He has loved us.

Christians engage in acts of service to the wider community as a natural consequence of their faith.

In recent years the foodbanks which have sprung up all over the country have largely been established by Christians of all denominations and traditions.

Equally people in the Church of England and other churches have supported the homeless, the unemployed, those affected by drug and alcohol misuse and many other social issues. In another field the Church of England has employed many more youth workers in the past decade whilst such workers paid from public funding have diminished considerably.

These things are not done to criticise lack of provision by government, whether national or local, but because there are needs which should be recognised and met. Such active service means the Church of England has first-hand local experience of the challenges in our communities throughout the country.

Our society needs intermediate institutions such as our churches which serve the common good and build strong community life. Everything cannot be left to government. Yet we often seem to assume governments are omni-competent. As we approach a General Election Christians should not place upon any government wholly unrealistic expectations.

We recognise every government is imperfect. Christians are not put off politics by that. We believe the world is good and created by God but disordered by human sin. Christians can therefore cope with defective institutions.

Viewed in simply human terms the Church is herself far from perfect. Yet Christians are always inspired by the vision of the Kingdom of God which, in the Lord's Prayer, we pray will one day come 'on earth as it is in heaven'.

It is that vision of peace and unity which means that in this Pastoral Letter we warn that we must not become a 'society of strangers' to one another but that, in our diversity, we should be a 'community of communities'.

In many parts of England, congregations in the Church of England are increasingly multi-ethnic, reflecting the international character of the Church and also that in Christ there is 'neither Jew nor Greek, neither male nor female, neither slave nor free'. (Galatians 3.28)

The danger of demonising racial or religious groups is considerable, especially at a time when international terrorism is a destabilising factor among the community of nations. We have to resist this, and there are many examples from the past to guide us, not least in my own city of Norwich.

When French Huguenots were expelled from their country in the 16th century, many settled in Norwich.

One of my predecessors gave them the chapel of the Bishop's Palace as their place of worship. It was a bold gesture but it sprang from the same Christian ethic which inspires this Pastoral Letter.