The donation, funded by the Foreign Office, Department for International Development and Ministry of Defence, comes in addition to more than pounds 20m pledged in aid since last spring.
Britain has also given pounds 3m to Ecomog, the mainly Nigerian force which has been fighting against rebel RUF soldiers who are trying to depose the president, Ahmed Kabbah. President Kabbah was exiled in 1997 after an RUF coup, but was restored to power last spring.
Mr Cook said yesterday: "The RUF has a very robust approach to democracy and freedom of expression - they lop off the arms of anybody who disagrees with them." Mr Cook said he had protested to the government of Liberia, which has been aiding the rebel troops.
He added that reports of British firms flying arms to the RUF had been referred to Customs and Excise for investigation. Although the UN arms embargo on Sierra Leone has been partly lifted, it still covers the rebel army.
There was controversy when President Kabbah was restored when it emerged that a British firm, Sandline International, broke an international embargo to ship arms to the country. The firm escaped prosecution after saying the Foreign Office was aware of its plans.
Much of Sierra Leone's capital has been destroyed in renewed fighting this month, and up to 200,000 people have been left homeless. Hundreds of Ecomog soldiers have been killed, and British sailors on the HMS Norfolk, sent to the region to give humanitarian aid, are reported to have seen bodies in the water.
Britain is giving logistical support to Ecomog and is sharing intelligence with its officers. The HMS Norfolk is on hand to provide transport for humanitarian aid, including the use of a helicopter. Some of yesterday's pounds 1m will be put to that use.
Clare Short, the International Development Secretary, was due to meet the Sierra Leone finance minister, James Jonah, in London last night to discuss how her department could help.Reuse content