When you are away on tour and you are miles away from home, getting a letter is a truly exhilarating experience. It makes you feel instantly closer to home and your loved ones. It is an ordinary thing to read a letter or a message, and when you are working in extraordinary and dangerous circumstances, ordinary can be a wonderful thing.
When I was in Iraq in the 1990s, there were no mobile phones or computers. We would wait, and wait, and wait to get mail. When it arrived it lifted everyone's spirits. It really is hard for me to articulate what a huge boost to morale it was.
And you know, you don't even need to know the soldier. I used to get letters from complete strangers talking about what was going on at home - seemingly mundane details like what was in the charts, etc - but it was such a comfort.
Now there is a website, called Thank You Soldier where you can send a thank you message instantly to a UK soldier. No need to sign in, create an account or register. You can just send a thank you message, which can be read by soldiers serving at home or overseas instantly.
Never underestimate the power of 'thank you'. On the 60th anniversary of D-Day my wife and I went to Normandy. We went to a battery and there met a veteran who had attacked the battery on D-Day (as it housed guns that were firing on the British landing on the nearby beach).
My wife shook the veteran's hand and said thank you, because her granddad had landed on that beach, and had survived that terrible day, thanks in no small part to the efforts of him and his fellow soldiers. The veteran started to cry. My wife started to cry too and apologised for upsetting him. "You didn't upset me," he replied "it was an honour for me to serve my country and I am humbled that you thank me for it."