Prime Minister Gordon Brown has written to Liberal Democrat leader Sir Menzies Campbell about British troops in Iraq and Afghanistan. Here is the full text:
Thank you for your letter of 16 August about Iraq and Afghanistan.
First of all let me say that like you I deeply regret and am saddened by each and every casualty and loss of life. Our armed forces deserve all our praise for the courage and dedication they show.
I disagree however with your contentions about UK strategy in relation to Iraq and Afghanistan.
As I have made clear in the House of Commons, UK forces, along with their coalition partners, continue to have an important job to do in Iraq, assisting the Iraqi Government and its security forces in delivering security and helping build their capabilities - military and civilian - so that they can take full responsibility for the security of their own country.
I believe that we continue to have clear obligations to discharge.
We are there at the express invitation of the Iraqi Government, implementing a UN mandate renewed last November in UNSCR 1723.
We, together with the rest of the international community, have undertaken to support the country's political and economic development through the UN-led International Compact for Iraq.
These are commitments it is not in our interests simply to abandon.
As I have made clear, decisions on UK force levels and posture in Iraq are dictated by conditions on the ground.
In the three provinces handed over to Iraqi control in Multi-National Division (South-East), the Iraqi authorities have proved themselves sufficiently capable of dealing with outbreaks of violence using a combination of security and political responses.
The situation remains challenging.
Our aim is that Iraqi Security Forces will be capable of delivering security across the South and that we will be able to draw down our forces.
It is wrong to say that the continuing presence of UK forces in Iraq will achieve little, or that they are severely restricted in what they can do.
UK forces in Basra continue to have the capability to strike against the militias and provide overall security.
They will continue to work with the Iraqi authorities and security forces to get them to the point where they can assume full responsibility for security.
We will support them in this endeavour, but it is for Iraqi leaders to make the political decisions and compromises which are essential to the future of Basra and their country.
So I am determined that our approach to Iraq should be based on the principle that we will fulfil our obligations to the Government and people of Iraq and the United Nations.
These obligations are set out in United Nations Resolutions.
That is why I reject your approach of a pre-determined exit timetable that would undermine our international obligations, as well as hindering the task of our armed forces and increasing the risks they face, and therefore would not serve our national interest.
Decisions on the ground will be made on the basis of advice from our military and other experts, taking fully into consideration the safety of our armed forces.
I will do nothing that puts at risk the ability of our armed forces, who have done and are doing a magnificent job, to accomplish their work.
And we will continue to work closely with the Americans and our other coalition partners to ensure security and then to fulfil the key overwatch functions - training/mentoring; protection of supply routes; and maintenance of a reintervention capability.
Turning to Afghanistan, I do not seek to hide the tough, dangerous and difficult tasks and terrain involved there, but as in Iraq I will strongly defend the integrity, bravery and intelligence with which UK commanders and forces are taking forward the strategy they have developed.
The UK has a strong force in Afghanistan - the second largest international force in the country, enabling us to make a contribution to the Southern region as a whole.
We are operating as part of a multi-national mission of some 37 nations, working with the Afghan Government to build strong and sustainable Afghan capacity and institutions.
The international community is united in its desire to prevent Afghanistan once again becoming a failed state.
Many nations, not just the UK, are offering military, financial and political assistance.
In Helmand alone, the Provincial Reconstruction Team has implemented over 130 projects bringing real benefits to local Afghans, including wells, roads, new and refurbished schools, updated healthcare facilities and better irrigation systems for local farmers.
There is much to do, but progress will be measured across a wide range of activity - covering governance, reconstruction, economic development and the building up of local security forces.