Whether the "war" in Afghanistan is winnable or not, it is bizarre that British troops are there at all. Logic might support the historical perspective that a country only fights those nations that invade them or threaten to invade them. There can be no doubt that Afghanistan poses a threat to the UK and to other nations – but then so do many other countries around the world. We do not plan to invade Korea, Saudi Arabia and all the others. Both the First and Second World Wars were fought against an enemy that was clearly planning to dominate Europe and where an invasion of the UK was extremely likely if we didn't action.  The invasions of Vietnam and Iraq broke that logical approach and we are paying the price.

Common sense would suggest that British forces must be taken out of Afghanistan ... and, in future, we must be clear about a policy that our armed forces are only used to defend this country.

So when and how do we plan to get out?  Because of NATO commitments and our responsibility to other allies, we cannot pull out tomorrow but we should be negotiating with our partners to develop a timeline to withdraw. Two years would seem to be reasonable. This plan would need to agree the process and the aims which might be attempted in such a period. If agreement cannot be reached with NATO partners, then it would seem logical that we would make a unilateral declaration. Indeed, this backstop position should be made clear to our partners in the negotiations. In other words, we either all agree a timetable to get out or our allies will have to face the fact that we will not be partnering you beyond such and such a date.

Should we worry about terrorism in our own islands?  The key reason put forward by the UK government for our being in Afghanistan is this threat to our homeland security. Also, this tends to be the one reason that is understood and accepted by the UK public. However, we do not need to be attempting to subdue the rebel forces and terrorists in every country of the world where they might pose a threat to the United Kingdom.

The answer to dealing with this threat is simple. Al-Qaeda and the Taliban hold such a threat over the British not because they plan to invade ... but because of their ability to influence and train those who can do their dirty work for them here.   These are mostly, UK citizens or residents. Therefore, we must simply adopt an inwards and exit visa policy which would mean that anybody wanting to visit either Afghanistan or Pakistan would need to apply for a visa. This would provide a national log of all of those who have this intention and the reasons why they wish to visit. Of course, many UK citizens have family in Pakistan but relatively few have in Afghanistan - though the border between these countries is notoriously porous.  Is that our problem?  Surely not; it is Pakistan's problem.

Therefore, to make this policy effective, we would need to negotiate with Pakistan to ensure that anyone who was given a visa (which would clearly have to be readily and simply available) to allow them to visit Pakistan would not be able to use this to cross the borders into Afghanistan. In other words, we would expect the Pakistan nation, in its own best interests, to restrict visitors going into Afghanistan unless they had the right exit visa.  Similarly, we would need stricter controls over those from Pakistan and Afghanistan who wanted to visit the UK.

In summary, we would make our borders much more watertight.  The effect of withdrawing our troops from Afghanistan would be a massive saving in costs.  A mere fraction of this could be used to improve the tightness of our border controls and, indeed,  the military could play a major part in helping to reinforce the work of the border control executives and the police.

Roger Haywood comments on public opinion issues.  He is a leading observer of the public relations and marketing industries.  He recently set up a website for young professionals seeking a top job in PR, based on his experience in recruiting and training hundreds of graduates: www.getstartedinpr.com

Haywood is the UK's leading issues analyst who originated the concept of issues management.  He is the only person to have chaired both the Chartered Institute of Public Relations and the Chartered Institute of Marketing.  He also helped form and chaired the world's largest network of independent business communications consultancies.