As you read this, Jamie Read and James Hughes will probably be defending the Kurdish city of Kobani in northern Syria.

Some 300 people have already died in the attempt. These young men are neither Kurds nor are they British soldiers.

They are - what are they? I could say they are idealists. I could say they are volunteers. I could say free-lancers. But really, having looked at their website, I think they are dreamers. In fact, before he arrived in Syria to take up arms against Isis, Jamie Read, from Newmains in Lanarkshire, wrote on his Facebook page: "This time next week I will be living the dream."

Jamie Read can't have paid attention to the commemorations of the First World War, nor watched the return of Second World War veterans to the beaches of D-Day. He can't have heard the horror recalled nor have seen the tears spilled. There was dignity and a terrible pity in the reminiscences of those elderly warriors but none was reliving "a dream".

So, are these freelance fighters risking their lives for the Kurds heroes in anyone's eyes but their own? Are their actions moral? Are they legal? And are the two in conflict?

Jamie Read and James Hughes are respectively the operations manager and managing director of an organisation called The Pathfinder Group Terrorism and Conflict Research Center (sic). Mr Read did military training in France and Mr Hughes, from Reading in Berkshire, was a serving soldier in Afghanistan. Their organisation boasts a website laden with high-minded messages starting with: "All that is necessary for the triumph of evil is that good men do nothing."

Its mission statement is "To Lead the Way" and it says: "We will go where the rest fear to go." This matters because it means that they are not dedicated to the defence of the Kurds alone but to fighting on the side of right wherever they decide that may be.

We know that some 500 young Britons have already gone to the region to fight alongside the jihadists. They, too, say they are fighting in defence of what is right. They, too, will take their fight to many arenas. So who decides where virtue lies? And is the moral cause really what is motivating young men to rush to battle?

Perhaps it is but I think something else is going on. I was reading the Game of Thrones series when Isis first appeared on our television screens. The characters in my book were being beheaded. On the television news so were western aid workers and journalists. And they were being beheaded by a jihadist with a London accent.

I was reading a fiction set in a mythical country in medieval times - and seeing the same horrors happening to real people in real time.Also in my books were young knights. These boys, and one girl, were teenagers but they itched to ride into battle, their flags flying, their swords at the ready to claim death or victory. And so they did.

In real life the young crave battle. Life is heightened when death is swirling around. There is nobility in a cause greater than ourselves and glamour in planning tactics, toting weapons, getting into a fight for real.

Some soldiers find it difficult to return to civilian life. They miss the adrenalin and a life in which they can forget the mortgage, pension plan and the fear of failure that stalks us all. In war they can be truly macho; and all in the name of what they claim to be good and right.

Because, remember, goodness and rightness are claimed by both sides and both sides will kill in their name.

Beneath the gloss of its website, The Pathfinder Group Terrorism and Conflict Research Center looks suspiciously like a two-man operation. In every image, Messrs Read and Hughes are dressed as soldiers and carrying weapons yet they say they seek an end to terrorism, stating: "May the world once more know peace." They say they plan to report from behind the line to the media, government and "university's" (sic) but they are not journalists. They are in battle but they are not serving soldiers. Their website, so full of bravado and romance, seems high on rhetoric and low on wisdom.

But whatever their folly, how should we regard their actions? Should we support them since Isis is our enemy and threatens attacks within the UK? Isn't the enemy of our enemy our friend? Isn't there a parallel with the Spanish Civil War and the young idealist Britons who went off to fight fascism?

The Prime Minister, David Cameron, has said there is a fundamental difference between fighting with the Kurds and joining Isis. After all, the UK is arming Kurdish forces. I would make two points.

Certainly, there is always a moral case for defending the undefended or weak against an aggressor. But many who were drawn to defend the Syrian population against Bashir Assad found their groups overtaken by extreme jihadists. They started out on the side of the angels (as the UK saw it). It's not where too many of them have ended up.

As for the legality, here too fog shrouds the issue. Sir Edward Garnier, former Solicitor General, told the Today programme yesterday morning that those who go abroad to fight other people's wars risk placing themselves in a legal limbo.

He pointed out they are not fighting on behalf of the UK so, if they kill, they could stand accused of manslaughter or murder.

Under the Counter Terrorism and Security Bill to be unveiled in the Commons tomorrow, returning jihadists could be refused entry for two years unless they submit to severe restrictions. They will face prosecution or close supervision under monitoring laws.

Should the same law apply to those fighting Isis? I really don't see why not. They are fighting in an arena where boundaries have shifted before. They have taken the law into their own hands and must face the consequences.

The Home Office treats different wars in different ways. Fighting in foreign conflicts is not necessarily an offence. It depends on the nature of the conflict and the individual's own activities. I ask myself how we would view these young people if they set themselves up as vigilantes to fight crime here. They might insist that they were setting out to protect innocent men, women and children against criminals. They might even manage to do that.

But what sort of a country would we be living in if individuals and groups randomly took power in parallel with the police force? By what right would they wield that power and in whose name would they mete out justice?

Yet isn't that what the Pathfinder Group is doing in Syria? The fiction of The Game of Thrones is all about war. But war isn't a game. These two young men will have to be judged by their actions when they return to Britain. It will be up to us and our system of justice to decide whether their fight was good, not them.