Beeb analyst Paul Reynolds takes a look back at the "Great Game" of the 19th century between Britain and Russia in Afghanistan.

An excerpt:

The 19th Century is not particularly useful if you are looking for lessons to be learned from previous British encounters with the Afghans.

There is one lesson from all foreign interventions in Afghanistan. It might look easy but it isn't

In the First Afghan War of 1832-42 (note its length), the British did manage to put a compliant ruler on the Afghan throne as a buffer against Russian influence, but it then all went disastrously wrong.

It ended when a British column of soldiers and camp followers some 16,000 strong was massacred as they tried to withdraw. One of the few survivors (some claim he was the only one) was a doctor, William Brydon.

The Second Afghan War (1878-80) was not much more successful. A British invasion did manage to put another helpful ruler in power but he abdicated following a rebellion and the British were forced out.

They did however leave behind another ruler, Abdur Rahman Khan, who accepted British influence to keep Afghanistan as a buffer state and yet who was strong enough lay the foundations of the modern state.

Different now?

The Russians did not fare any better in the attempt to support a communist government in Afghanistan in the late 20th century. That adventure ended in withdrawal and the defeat in Afghanistan came to be part of the wider collapse of communism.

Of course, the argument today is that it is all different now. There is a democratically elected government in Kabul, it is stated, and the Western troops are only there to help and even then in small numbers.

We are not talking of the tens of thousands of British troops that invaded in 1878 or the Russians in late 1979.

But there is one lesson from all foreign interventions in Afghanistan. It might look easy but it isn't.