The three Benelux countries, Belgium, Netherlands and Luxembourg, Wednesday (4 March) agreed to share surveillance and protection of their air spaces, in the first agreement of its kind among EU countries.

Starting from 2017, Belgian and Dutch air forces will take turn to monitor the Benelux airspace. Luxembourg has no military airforce and will only open its air space to its neighbours’ jets.

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The common missions will involve the so-called 'Renegade' procedure aimed at identifying suspect civil aircrafts that might pose a terrorist threat.

"The agreement is a step forward in the intensification of European military cooperation", said Belgian prime minister Charles Michel in a statement.

"We work together to make sure that European security progresses. The terrible events of the past months motivate us greatly", said his Dutch counterpart Marc Rutte, referring to recent terror attacks in France and Denmark.

The Benelux agreement is a novelty in European defence policy because it is the first time countries agree that a foreign airforce may operate and potentially shoot down a civilian plane over its territory.

This raises important legal issues set to be much debated in the three countries' parliaments during the ratification process.

The agreement specifies that the decision to shoot down a civil aircraft will remain under the responsibility of the competent national authorities: the prime minister in Belgium and the security and justice minister in the Netherlands.

Luxembourg has already excluded the use of lethal force over its territory.

This agreement for shared missions will come as a relief for the Dutch air force. The old F16 fleet is supposed to be replaced by 2019 by new F35 jets, but the programme has been running late and costs have rocketed.

Belgium also plans to renew its F16 fleet by 2018. The French Rafale is a candidate but the enhanced cooperation with Netherlands might tilt the decision towards the American F35.