Defence giant BAE Systems has announced a contract valued at £5 billion to supply 24 Typhoon aircraft to Qatar, safeguarding thousands of UK jobs.
The deal to supply Typhoon aircraft to the Qatar Emiri Air Force includes a support and training package.
The contract is subject to financing conditions and receipt by the company of first payment, expected to be fulfilled no later than mid-2018, with delivery expected to commence in late 2022.
Around 5,000 workers in the UK are employed on building the Typhoon, mainly at Warton in Lancashire.
BAE Systems is the prime contractor for both the provision of the aircraft and the agreed arrangements for the in-service support and initial training.
Defence Secretary Gavin Williamson, who oversaw the signing of the deal with his Qatari counterpart, Khalid bin Mohammed al Attiyah, said: "It is a great pleasure to sign our biggest export deal for the Typhoon in a decade.
"These formidable jets will boost the Qatari military's mission to tackle the challenges we both share in the Middle East, supporting stability in the region and delivering security at home.
"As we proudly fly the flag for our world-leading aerospace sector all over the globe this news is a massive vote of confidence, supporting thousands of British jobs and injecting billions into our economy.
"The contract will secure work on the production line at Warton into the next decade."
The Defence Secretary also agreed a package of training and co-operation between the air forces which will see them working together more regularly, including Qatari pilots and ground crew training in the UK.
Qatar is the ninth country to buy the Typhoon, with this year seeing the first delivered to Oman.
Charles Woodburn, BAE Systems chief executive said: "We are delighted to begin a new chapter in the development of a long-term relationship with the State of Qatar and theQatar Armed Forces, and we look forward to working alongside our customer as they continue to develop their military capability.
"This agreement is a strong endorsement of Typhoon's leading capabilities and underlines BAE Systems' long track record of working in successful partnership with our customers."