France and the UK: A Decade of the Lancaster House Treaties

On 2 November 2010, Prime Minister David Cameron was standing alongside President Nicolas Sarkozy in the gilded splendour of Lancaster House when he declared that ‘today we open a new chapter in a long history of cooperation on defence and security between Britain and France’. The leaders had just signed two landmark treaties. 10 years on, what has been achieved and what are the prospects for the next decade?

The ceremony held on this day exactly a decade ago rounded off five months of intensive work for the UK’s new National Security Council which I had set up for the Cameron government when it came to power in May 2010. In October, the government published a National Security Strategy and a Strategic Defence and Security Review, with five-year budget settlements. Two weeks later came Lancaster House. The two treaties reflected the vision and drive of the two leaders. Sarkozy had brought France back into NATO’s military structure in 2009. Both leaders wanted to use this to build up pragmatic cooperation between Europe’s two major military powers. Cameron was also keen on saving money by doing more joint military procurement with the French.

Say Less, Do More: Nuclear Cooperation

One of the treaties dealt with nuclear cooperation. It got less attention at the time, but was of greater long-term significance. The UK and France are Europe’s only two military nuclear powers. But they have kept their nuclear procurement and operations completely separate. In 2010, Cameron and Sarkozy were both looking for a powerful signal of their new strategic partnership. So they decided to establish the Teutates project, to build a single shared facility in France for testing the safety and reliability of their nuclear warhead designs. Cameron forecast several hundred million pounds of savings.

By 2018, the UK and France were using the same vast radiographic machines for their national experiments. The full site is due to be completed by 2022, and the treaty is valid for 50 years. All that time, the UK and France will be mutually dependent for a critical aspect of their nuclear deterrents. There could be no stronger signal of confidence that the vital national interests of the two countries will remain aligned whatever the ups and downs in the political relationship.

Broader Defence and Procurement Cooperation

The main aim of the second treaty was to launch practical work in two areas: strengthening cooperation between the two armed forces, and joint procurement of equipment. One of the real success stories of the Lancaster House process has been much closer operational cooperation between the two militaries. The main vehicle for this was developing a Combined Joint Expeditionary Force (CJEF), capable of deploying a joint brigade-level force with air and naval assets and conducting high-intensity combat operations. Bringing this force up to full operating capability (expected by the end of 2020) has involved regular joint exercises and exchanges of personnel. As a result, units across the two armed forces have trained together, communications problems have been ironed out, and personal links established up to senior levels.

The two countries now have a fighting force which they could jointly deploy if the two governments decided to act together. In the meantime, the two armed forces are operating together increasingly often: from air strikes against the Islamic State in Syria, joint naval deployments, humanitarian relief and French participation in the UK-led NATO Enhanced Forward Presence in Estonia.

Progress on defence equipment cooperation has by contrast been disappointing. The initial high hopes that the UK and France could develop a joint Future Combat Air System (probably a large drone) have come to nothing. Instead, the French turned to a joint project with Germany on a next-generation fast jet, and the UK is pursuing the Tempest programme with Italy and Sweden. Once again, Europe will be trying to sustain two competing fast jet programmes.

Cooperation on missiles has made more progress, particularly on a new anti-ship missile for the two navies. But the ambitious plans for industrial cooperation between the UK and France have been a casualty of Brexit and the wider geopolitical environment. French energies under President Emmanuel Macron have turned towards European strategic autonomy. The UK’s refusal to seek any structured cooperation with the EU on security and defence matters makes it inevitable that European defence industrial cooperation will develop without the UK.

Looking Ahead

Where does that leave future UK–French defence cooperation? The nuclear relationship is underpinned by the Teutates deal. There is scope for the two countries to consult more closely on nuclear deterrence, given that Macron’s offer of a European dialogue about nuclear defence and deterrence seems to have fallen largely on deaf ears in other EU countries. The CJEF has been successful in strengthening links between the armed forces. If European countries ever needed to deploy forces into combat, it would be France and the UK in the lead. Macron’s suggestion of a European Intervention Initiative outside the EU framework looks designed to give the UK a forum for operational cooperation.

Brexit does not weaken the case for Europe’s two major military powers work together. The new emphasis on European technological sovereignty in the light of the threat from China and the post-Covid need for resilience should have been a further incentive for UK–French industrial cooperation. But in practice Brexit has pulled in the opposite direction. There is no appetite in London for structured dialogue with the EU on defence and security, while Paris is busy promoting EU-based autonomy.

It is striking that the two governments did not plan a major event on the 10th anniversary of Lancaster House to celebrate the achievements and relaunch cooperation for another decade. That may partly be a casualty of the coronavirus pandemic. But it has to be seen mainly as confirmation that the bilateral defence relationship has lost momentum, collateral damage in the UK’s chaotic departure from the EU.

In time, the bruises will fade. But it is likely to be another decade at least before a French president again stands beside a British prime minister and echoes Sarkozy’s call at Lancaster House for Franco-British leadership: ‘we have to provoke change, we have to lead change, we have to have vision, and we have to be very ambitious’.

The views expressed in this Commentary are the author's, and do not represent those of RUSI or any other institution.