Ankara and London signed a preliminary deal for the Eurofighters in July, which are manufactured by a consortium comprising the UK, Germany, Italy and Spain and led by Britain's BAE Systems.
Turkey and the UK signed a deal worth £8 billion pounds (around €9 billion) for 20 Eurofighter Typhoon jets on Monday.
The agreement to enhance Turkey's air capabilities was signed in Ankara during British Prime Minister Keir Starmer’s first visit to the country and marks the first new order of UK Typhoons since 2017.
"Our countries may sit at either end of Europe, but we’re strong partners, working more closely together now than ever before," Starmer said during a signing ceremony alongside Turkish President Recep Tayyip Erdoğan.
"This will bolster security across NATO, deepen our bilateral defence cooperation and boost economic growth here and in the United Kingdom, securing 20,000 British jobs,” Starmer added. “I am proud that British typhoons will form a vital part of the Turkish Air Force for many years to come."
Erdoğan hailed the agreement as a "new symbol of the strategic relationship between us as two close allies."
Starmer added that the agreement provides the option for the sale of more jets in the future.
Ankara and London signed a preliminary deal for the Eurofighters in July, which are manufactured by a consortium comprising the UK, Germany, Italy and Spain and led by Britain’s BAE Systems.
The deal followed Germany's reported decision to lift its longstanding opposition to the sale of the jets to Turkey.
Last week, Erdoğan toured three Gulf nations and held talks on the potential acquisition of used Typhoons from Qatar and Oman.
In addition to the 20 new Typhoon aircraft, Turkey plans to purchase 12 second-hand jets from Qatar and 12 others from Oman, Turkey's A Haber news channel citing Defence Minister Yaşar Güler said.
New charges for İmamoğlu
Starmer's visit comes as Turkish prosecutors on Monday filed new charges against Istanbul's jailed mayor, Ekrem İmamoğlu, accusing the politician seen as a key challenger to Erdoğan of involvement in "espionage" activities.
İmamoğlu was arrested in March on corruption charges, which he strongly denies.
Turkey's main opposition Republican People's Party (CHP), has criticised European governments for their muted responses to what they see as a politically motivated government crackdown on İmamoğlu and other jailed opposition mayors. Erdoğan's government insists the courts operate independently.
Starmer's spokesman, Tom Wells, said the UK expects Turkey "to uphold its international obligations and the rule of law, including the right to a fair trial," adding that London had raised the issue of the arrests with Turkey's government "at a number of levels."
"We have always been very honest with our counterparts over areas of divergence," Wells said when asked about Turkey's human rights record. "Economic partnership can co-exist with frank dialogue on areas of disagreement."
Turkey views the purchase of Eurofighters and other advanced jets as an interim solution until its domestically developed fifth-generation KAAN fighter jet becomes operational. That is expected no earlier than 2028.
Turkey, a member of the NATO military alliance, also seeks re-entry into the US-led F-35 fighter jet programme. It was excluded in 2019 due to its purchase of Russian-made S-400 missile defence systems, which was deemed a security risk to the F-35 programme.
Erdoğan raised the issue of the sale of F-35 fighter jets during a recent meeting with US President Donald Trump at the White House.