The Sultanate of Oman has finally signed a long-awaited contract to buy 12 Eurofighter Typhoon fighter aircraft.

The deal, signed in Oman on Dec. 21, also includes eight Hawk jet trainers and in-service support. In all, the deal is worth £2.5 billion ($4.06 billion).

Manufacturing of the aircraft is due to begin in 2014, with first deliveries in 2017. The new Typhoons will replace Oman’s aging fleet of Sepecat Jaguars, while the new Hawk Advanced Jet Trainers (AJTs) are likely to replace the fleet of Hawk 100s used for training.

Negotiations with Oman have been continuing for more than three years, and were recently complicated by difficulties with a trio of corvettes destined for the Omani Navy that were being built in the U.K.

The sale of the Typhoons is part of a major drive to sell British defense equipment to Middle Eastern countries. U.K. Prime Minister David Cameron continues to lobby the government in Abu Dhabi for a possible sale of the Typhoon for the United Arab Emirates and was reportedly in meetings with officials about the aircraft during a recent visit to Dubai in November.

Hailing the Oman deal, Mr Cameron said: “Boosting exports is vital for economic growth and that’s why I’m doing all I can to promote British business in the fastest growing markets so they can thrive in the global race.”

“Every country in the world has a right to self-defense and I’m determined to put Britain’s first-class defense industry at the forefront of this market, supporting 300,000 jobs across the country,” Cameron said.

Along with the sales drive to the UAE, BAE Systems is continuing to work on the sale of a second batch of Typhoons to Saudi Arabia. However the company is struggling to reach an agreement on price, and it warned earlier this week that its 2012 earnings could be affected should a pricing agreement not be reached.

Saudi Arabia has so far taken delivery of 24 out of 72 Typhoons it ordered under the Al-Salam deal, reportedly worth around £4.5 billion. Test flying has now commenced on the first batch of aircraft in the final 48 destined for Saudi Arabia. These aircraft had been due to be built in-country, but a contract change announced earlier this year will see the aircraft now being completed in the U.K. at BAE Systems facilities in Warton, Lancashire.