British troops are to pull out of Afghanistan by 2014, under a secret blueprint for drawing down coalition forces that is set to begin in a matter or months, it emerged last night. A leaked communiqué – a copy of which has been seen by The Independent on Sunday – reveals how President Hamid Karzai will announce the timetable for a "conditions-based and phased transition" at the International Conference on Afghanistan to be held in Kabul on Tuesday.

The meeting – which is set to map out the way ahead for the war-torn country – will be attended by US Secretary of State Hillary Clinton, UN Secretary-General Ban Ki-moon, the Foreign Secretary, William Hague, and foreign ministers from more 70 countries. An agreed version of the document, marked "not for circulation", was sent to senior diplomats yesterday by Staffan de Mistura, the United Nations Special Representative in Afghanistan.

It states: "The international community expressed its support for the President of Afghanistan's objective that the Afghan National Security Forces (ANSF) should lead and conduct military operations in all provinces by the end of 2014." This comes just weeks after Mr Hague hinted that British troops could leave by 2014, and is the first formal confirmation of the timescale that governments have been working towards behind the scenes to agree in recent months.

The communiqué goes on to pledge that the international community will continue to "provide the support necessary to increase security during this time, and the continued support in training, equipping and providing interim financing to the ANSF at every level to take on the task of securing their country". It adds: "The government of Afghanistan and the international community agreed to jointly assess provinces, with the aim of announcing by the end of 2010 that the process of transition is under way."

The announcement is one of many issues surrounding development and governance that will be addressed at the conference, as well as an $800m (£523m) five-year Afghan peace and reintegration programme that "aims to reintegrate in five years up to 36,000 ex-combatants and to reach 4,000 communities in 220 districts of 22 provinces". The document also outlines short-term goals for coalition troops. These include combating the opium trade by maintaining the provinces that are currently free of drug cultivation, and increasing the number of poppy-free provinces in Afghanistan to 24 within 12 months. It also describes transparent elections in future as a matter of paramount importance.

President Karzai will tell delegates that the conference represents "a turning point" in Afghanistan's "transition to an era of Afghan-led peace, justice and more equitable development". He will also pledge that "expanding the day-to-day choices and capabilities of the Afghan people and ensuring their fundamental rights" will "remain the cornerstones of my government's approach to peace-building and comprehensive recovery".

A senior source in the British military confirmed yesterday that the blueprint was "a significant map laying out the stages on the way to withdrawal". He said: "The British government has been talking in terms of a 2014 withdrawal, but nobody has been able to produce a timetable identifying how and when things would happen. This document demonstrates that there is a will in the international community to have it done by then.

"I cannot stress too much the importance of them having a strategy to do that. In the past, the international community has come up with dates by which they wanted something to happen, but because they had no plans to back them up, too many deadlines were allowed to slip."

Colonel Bob Stewart, the former UN commander in Bosnia and now MP for Beckenham, said last night: "Whether we can actually get out before 2014 is a bit like asking how long is a piece of string. The aspiration is actually to be out by 2015 – if they can do it any quicker, the better. I understand why we went in, to neutralise that part of the world and the threat of attack. But I want us out as soon as possible, and so does the rest of the country."

The new strategy came as it was reported that Britain is to divert hundreds of millions of pounds of aid away from other countries to help Afghanistan. The International Development Secretary, Andrew Mitchell, is to boost aid to Afghanistan by 40 per cent, The Observer reported this weekend.

Four more British servicemen were killed in separate incidents in Afghanistan this weekend, the Ministry of Defence said yesterday. A member of the Royal Dragoon Guards and a soldier from the Royal Logistics Corps died in separate blasts in the Nahr-e Saraj district of Helmand yesterday.

On Friday, an airman from the RAF Regiment died in a road accident near Camp Bastion in Helmand, and a marine from 40 Commando Royal Marines died in an explosion while on foot patrol in Sangin. Next of kin have been informed. The latest deaths, taking the total to 322, have added to a summer of escalating violence as Afghan and coalition forces step up patrols in the Taliban-dominated south in a push to take control of the traditional insurgent stronghold. Last month was the deadliest for coalition soldiers since the war began in 2001, with 103 killed.

The killing of three UK soldiers by a rogue Afghan recruit in Helmand on Tuesday highlighted the scale of the task of building up a local security force capable of maintaining security, and has raised tensions between coalition soldiers and their Afghan allies.

Success is by no means certain, with the strategic plan of creating an Afghan security force capable of taking over from coalition forces fraught with difficulty. Afghan police and soldiers have been infiltrated by the Taliban at senior levels, and the forces are plagued by corruption and drug addiction. Already this month, as the IoS revealed, the system for assessing them is so flawed that it has been scrapped, and a report by the US Special Inspector General for Afghanistan Reconstruction (Sigar) warned that Afghan assessments "have overstated operational capabilities".