Dear David Cameron, Nicola Sturgeon, Ed Miliband and Barack Obama,

I am writing to you as leaders of the Western world, with a simple request. When are you going to appoint your first Christian rights envoy? I'm sure you must be aware of some of what is going on. The beheading of 21 Christians in Libya last week is just the latest gruesome video killing. But that is only the tip of the iceberg. There is much more going on that is unseen. The Centre for the study of Global Christianity in the United States estimates that 100,000 Christians per year are killed simply for being Christian. 100,000!

Christians face official discrimination in 139 countries – that is over 75 per cent. In India Christians have been regularly murdered by extremist Hindu militias, in China the Communist Party has stepped up a programme of destroying churches and has banned Christians from being in government; in Iraq the number of Christians has been cut from 500,000 to less than 100,000; in Syria many Christians have been forced to flee their homes; in Nigeria the killing of Christians has become so routine that our it hardly registers on our media, unless there is some particularly gruesome aspect to it. And there is much, much more.

So I have a simple question. Why have you done nothing for the most persecuted people in the world? And it seems to me you propose to do nothing. And yet you have a responsibility. After all you decided to bomb Libya to get rid of Gaffadi, thus leaving a power vacuum that has resulted in the extremist Jihadists who beheaded the Egyptian Copts. You encouraged the Arab Spring in the naïve hope that the people of the Middle East would enter into a Western style liberal democracy if only they got rid of their dictators. And it is British and US government policy that is at least partially responsible for the decimation of the ancient Christian community in Iraq.

But it is not just the responsibility our governments have because of its policy. There is also something called basic humanitarianism. Why have you not offered to actually do anything? You shrug your shoulders and say 'what could we do'? And yet I sense a little inconsistency here.

You have recently promised to lend your full support to the idea that Britain would make LGBT rights a central plank of British and American foreign policy. My understanding is that you are not only going to make this a central in international diplomacy, but you also want to link this to aid and to appoint a kind of ambassador for this purpose. First Minister, you have said that you want to appoint an LGBTI envoy (although I wonder why you left the Q and the A out, as these are apparently the latest necessary letters that need to be added to show how tolerant one is). President Obama you have said the same thing. Mr Miliband, not to be outdone, you have just appointed Lord Cashman as your LGBTI envoy for the Labour Party.

I have no doubt that you are sincere in your desire to advocate and fight for the rights of the 1 per cent of the population that are LGBTIQ – and please don't misunderstand me. I too have written against the homophobia of Putin and the cruelty of the proposed Uganda 'gay' bill. I am not arguing that you should not seek to deal with these things. But there is also part of me that thinks that that is easy for you. It plays well at home, it gets you accolades in Pink News, nice editorials in the Guardian and New York Times, lets you congratulate yourself on how humanitarian and moral you are, and most of all, it costs you virtually nothing. It's cheap populism. But for the third of the world's population who are Christian you seem to have little time or money. You don't want an envoy for them because that would be 'discriminatory'. Sure, you think it is terrible what is happening and you will 'like all right thinking people' deplore what is going on. But will you actually do anything?

You could put pressure on 'friendly' nations who continue to discriminate against Christians, in the same way that you propose to put pressure on those who discriminate against homosexuals. Like Malaysia where for a Malay to become a Christian is a crime punishable by the State, or Saudi Arabia where to even have a Bible is punishable by flogging, or Pakistan where the way to get rid of a neighbour you don't like is just to accuse them of blasphemy. You could refuse aid to countries where such discrimination is enshrined in law. And please, instead of just sending planes to drop bombs on people, who then get mad at the 'Crusader' planes and take it out on the poor Christian minorities on the ground, you could actually agree to take many more than the 50 Syrian refugees that Britain so far has accepted.

Prime Minister Cameron you claim that this is a Christian country – you do realise that turn the other cheek is an instruction for individual Christians, and not a manifesto for foreign policy? Mr Milliband, thanks for speaking out on this subject, can you now tell us what actions your government would take if elected? First Minister Sturgeon – can you indicate that you will set up a Scottish government envoy to argue against religious discrimination (of all sorts) and to ensure that the Scottish government will have nothing to do with those who persecute people because of their faith? President Obama, will you use the considerable power of the US to seek human rights for Christians (and other religious minorities as well)? Perhaps if you put as much energy into defending persecuted Christians, as your Secretary of State and wannabe successor does into promoting abortion throughout the world, it might make a difference?

My fear is not just that you are engaging in populist tokenism, but that you really are prepared to engage in this new Western Liberal Imperialism, where your default unthinking position is that it is self-evident that your values are the real absolute values of all civilised, right thinking people. It's not just that you think democracy is good, or that corporate capitalism is the only economic system that can work, (you may be right but we are allowed to question?), but that you also believe that your liberal ethics are the absolutes that the entire world MUST follow. This results in you playing the dangerous game of moral equivalence based only on your own absolutist ethics. You equate those who behead people of a different faith with those who believe that homosexual marriage is wrong. And it is so hypocritical. You are prepared to sell bombs to those who kill/imprison people who become Christians, and yet deny bread to those who think that marriage should be between a man and a woman or question whether abortion really is good for the baby and mother's health!

Meanwhile we do what we can for our persecuted brothers and sisters throughout the world. We pray. We send what aid we can. We would love to offer hospitality (if you would let our stupid immigration laws take account of what they are facing). And we long for the day when some sane Western politician somewhere will have the guts and gumption to stand up and say: "No, enough. We are not prepared to ditch the foundation and basis of our Western civilisation. And we are not prepared to fund, support and encourage those who kill in the name of their religion."

And we pray for you as God's servants, as it says in 1 Timothy 2: "I urge, then, first of all, that requests, prayers, intercession and thanksgiving be made for everyone – or kings and all those in authority, that we may live peaceful and quiet lives in all godliness and holiness.This is good, and pleases God our Saviour, who wants all men to be saved and to come to a knowledge of the truth."