Why are British lives considered more important than foreign lives by the media?

In the daily mirror on Saturday 17Th of October an article by Tony Parsons caught my eye. The article was called "This damn war is not worth one British life" It talked about the war in Afghanistan. It said "The only reason I can see us being in Afghanistan is the reason we were part of the invasion of Iraq. To suck up to America" A bit of a simplistic deduction typical of newspapers like the mirror but one I can understand. But that's beside the point, the point I'm making comes later in the article.
At the end it says "That wretched country is not worth one British life" Why is it that the media only ever care about British lives? If we look at the facts there have been 395 British casualties in the war on terror. Whereas there have been estimates of 20000-50000 Afghan casualties and estimates of 600000-1000000 Iraqi casualties. Iraqi and Afghan civilians can't change the fact that their country is at war. I don't want to sound like a hippie but the cost of a life (that is if there is such a thing) Shouldn't be determined by a persons nationality. When will we learn that we are not the only people who matter? Thank you for your time.