Dear Mr Cameron,

I realise that you have a difficult job and that in the real world governing Britain is no picnic. Balancing 'British values' with the realpolitik of the world we live in is a truly Herculean task.

That is why we in the Christian Church pray for you. We are commanded by God to "pray first of all for kings and those in authority, that we may live peaceful and quiet lives in all godliness and holiness" (1 Timothy 2:2). Be assured you and your government are much in our prayers.

As a citizen of this British democracy I would however like to express some concerns about the visit of President Xi Jinping of China. I realise that you want to trade with China and to get as much investment as possible. But the question is, at what price does this investment come? You have spoken again this week about the need to maintain British values and to root out those within the UK who would oppose these values.

I am never quite sure what you mean by these, but I assume it is safe to regard democracy, freedom of speech, freedom of the press, and freedom of religion as being crucial parts of them. And therein lies the problem.

President Xi Jinping was secretary of the Central Military Commission of the Chinese Communist Party when the Tiananmen Square massacre of those campaigning for democracy occurred in 1989. His wife Peng Liyuan sang to the troops who participated in the massacre afterwards. There has been no apology and no recognition of guilt, and no movement towards a democratic system. It seems as though the British value of democracy comes second to that of money when it comes to dealing with rich and powerful nations.

Gao Yu is a 71-year-old journalist who has been sentenced (for the third time) to seven years in jail for leaking state secrets. She is one of many journalists and bloggers who have been detained by the Chinese authorities. China has one of the most repressive media cultures in the world. And yet to my embarrassment I note that Tuesday's Daily Telegraph contained a full colour supplement sponsored by China Daily and that its main pages contained nothing critical about China. Has it really come to this? That another countries State media can buy off the free British press? And can the British government be bought in the same way?

While there are enormous advantages in having Chinese money invested in British universities, businesses, media and even sport, there are also disadvantages. How ironic that on the day President Xi Jinping arrived in Britain it was announced that 1,200 British steel workers were to lose their jobs, largely because of cheap subsidised Chinese steel being dumped on the European market.

And what about the announcement that the Chinese are to run British nuclear plants, beginning with Hinckley Point in Somerset with China covering 30 per cent of the cost? Maybe this is a good deal for the British taxpayer but I have my doubts. At a financial level it seems unwise (and against the principles of the free market) to guarantee a price of £92.50 per megawatt hour – more than twice the current cost. It is the British people that will end up paying for the folly of subsidising Chinese companies.

And at a security level – why, when we are about to pay billions to renew a nuclear missile system to deter countries like China with nuclear missiles from attacking us, are we handing them control of nuclear facilities in this country? Given that many countries, including the US, have expressed concern about Chinese cyber attacks on infrastructure like power plants, is it not a bit daft to hand them the keys?

I know that Xi Jinping is a big football fan, even making it a compulsory part of education, but was there really any need for your Chancellor George Osborne to give £3 million of British taxpayers' money to China to help promote the Premier league? One wonders if the richest football league in the world really needs its government to be handing out taxpayer's cash to promote it!

As a Christian leader I am also greatly concerned about the persecution of Christians (and indeed other faiths) in China. For example, in the Eastern province of Zhejiang more than 400 churches have been demolished in the past 18 months.

It somewhat sticks in my throat that one of the architects of the Tiananmen massacre is being wined and dined in great style by the United Kingdom, while my brothers and sisters in China are being imprisoned and discriminated against because of their Christian faith. How does that square with British values?

Prime Minister, you have made a great deal of those values. Could you tell us how giving a state visit to the leader of a country that specifically goes against them makes any sense? Why was Xi Jingping allowed to address both houses of Parliament? Why is he being treated as a great democratic leader of a free country? Do British 'values' only matter when money is not involved? Or when we seek to impose 'liberal values' such as homosexuality and abortion on poorer countries?

If you really do intend to make the UK China's 'best partner in the West', could you at least make sure that you do not sell the soul of the United Kingdom in order to gain 'the world'?

It's a simple question. What price British values?

David Robertson is the moderator of the Free Church of Scotland and director of Solas CPC, Dundee.