On August 21 this year, a Rubicon was crossed. David Cameron ordered the summary execution of two British citizens, Ruhul Amin from Aberdeen, and Reyaad Khan from Cardiff. Both were killed by RAF drone strikes in Syria. The justification for these attacks are obvious and I suspect most Britons will accept them. In my view they are a dangerous precedent and further evidence of Britain moving away from its Christian traditions and ethos.

There are many disturbing aspects to this case. First, it was an execution without trial or due process. Second, it took place not because of crimes already committed, but because of 'intended crime'. Cameron stated, "their intention was the murder of British citizens. So on this occasion we took action". Third, it took place in a country which we are not at war with, and which the British Parliament voted against taking military action against.

Now of course the Prime Minister will justify the action by saying that he can be trusted and that he should be allowed to order executions based upon the best available evidence. And many people in the UK, including many Christians, will go along with that because we buy into the simplistic narrative that ISIS are the bad guys and we are the nice good people. But like all simplistic narratives there is an enormous danger in following it. Do we really want to grant to the British Prime Minister the right to be judge, jury and executioner all on his own? Should he have the right to order the execution of British citizens (or indeed any citizens) without trial? In a 'normal' war it is countries that we are at war with, and there are basic rules of warfare to be followed. With ISIS and Islamic terrorism that of course does not apply – but will suspending the normal rules of war, or indulging in state sponsored execution, not just give to ISIS what they are looking for, further justification for their hatred and distrust of the West?

And there is a further disturbing aspect to this precedent. When does it stop? If we are expected to trust the British Prime Minister to act as judge, jury and executioner in this regard, why not in other respects? What if one day, down the road, the British government decided that those who did not accept 'British values' were a threat to the state and could be dealt with in such a summary way?

The pillars of the British state are democratic rule of parliament, with the head of state being a Christian monarch, and an independent, fair legal and judicial system. Over the past decades there has been a constant undermining of the authority of parliament, and a subsequent increase in the power of the 'executive'. It is also questionable how much the independence and fairness of the judicial system has been preserved. This attack undermines both parliament and the judicial system. Parliament had already voted against military action in Syria, and I don't believe that ordering an execution of British citizens in another country because of information that they intended to attack Britain is legal.

The trouble is that in order to justify this, the Prime Minister and others, will point to the horrors of ISIS. Indeed. But to respond to horror with something that is also horrific, is at best a naïve approach. And our government's naivety has already cost this country and the world dear. We thought that actions such as invading Iraq, supporting the Arab Spring and bombing Libya would result in peace loving democracies being established in North Africa and the Middle East. Look at the consequences of that! Do we seriously think that adopting a policy of summary execution at the whim of the Prime Minister is going to turn out any better?

Earlier this week we were informed that Cameron regarded those who opposed same-sex marriage as 'Neanderthals'. I regard those who think that if you just hit those who threaten to club you with a bigger club, that is somewhat Neanderthal!

There is enormous confusion at the heart of government, and a dangerous reliance on their own omniscience and omnipotence. The photo of Aylan Kurdi, drowned while crossing the Mediterranean, is credited with changing British policy on refugees. If only life were that simple. What many people seem to have forgotten is that the wee boy was a Kurd. The Western powers just signed an agreement with the Turks to use their airbases and to let them do airstrikes into Iraq. So far the Turkish air force have flown three strikes against ISIS, and 300 strikes against the Kurds, where doubtless more little Kurdish children have died. But we won't see their photos on the front of the Sun. And if we begin this policy of summary execution by drones doubtless there will be other children caught in the crossfire, whose names and photos we will not see.

Military drones cost millions of pounds and running them costs tens of thousands. Meanwhile the government says we can only afford to take 4,000 refuges per year (the Germans say they will take 500,000). We can't afford to take refugees but we can afford to execute suspected terrorists in another country.

The Christian Church cannot, and should not want to, run government. But we can and should pray for prime ministers and those in authority. And in a free democratic society with a strong Christian tradition we should be the prophets who cry out to those in power – 'not in our name'. Yes, welcome the refugees in our name, but don't execute in our name.

David Robertson is Moderator of the Free Church of Scotland and a regular contributor to Christian Today.