A Royal Air Force C17 aircraft based at Brize Norton in Oxfordshire has been deployed to fly 500 tents from Dubai to flood-hit Pakistan.
The RAF is helping with the aid effort in the country, where severe flooding has affected millions of people.
The tents have been flown to Islamabad, from where they will be driven to the Peshawar region.
The tents, provided by the Department for International Development (DFID), will provide shelter for 2,500 people.
The region's worst floods for 80 years have killed at least 1,600 people.
The tents can be erected within half an hour and are designed to withstand extremely heavy rainfall and cold conditions.
The C17 is the RAF's largest transport aircraft capable of carrying 73,800kg of freight and 138 personnel.
It has already been operating every day in the region providing logistic support, ferrying supplies and personnel to UK forces in Afghanistan.
Wing Cdr Simon Edwards, from 99 Squadron, said: "I am pleased that [we] have been able to help in this important task... in support of the vital humanitarian mission to Pakistan."
George Turkington, DFID's head of the Pakistan office, said: "These 500 tents, along with the 2,000 we've already provided, will give urgently needed shelter to thousands of people whose homes have been washed away by the monsoon floods."