The defence secretary, Michael Fallon, has announced a £100m contract to improve the performance of a new generation of drones for the RAF.

The government disclosed as part of last year’s defence review that it would double its drone fleet from 10 to 20 and the existing Reapers will give way to an updated version, the Protector, capable of remaining airborne for 40 hours and due to come into service in around 2020.

The UK is using drones in both Iraq and Syria to target members of Islamic State.

Fallon was speaking in California at the annual Reagan National Defence Forum, which brings together leading members of the US defence establishment. It potentially provides the first opportunity for a British cabinet minister to engage with the incoming Trump administration.

Fallon, who knows the incoming defence secretary, General James Mattis, will have a chance to gauge any potential shifts in defence thinking in the new administration.

Trump created alarm in Europe by making comments on the campaign trail in which he cast doubt on the whole basis of Nato, suggesting the US might not necessarily come to the aid of a member under attack. His seeming willingness to engage with the Russian president, Vladimir Putin, has also contributed to concerns in Nato.

Fallon was scheduled to meet the present US defence secretary, Ash Carter, and the chairman of the US joint chiefs, General Joseph Dunford, at the conference.

The new drone contract is with the California-based drone company General Atomics Aeronautical Systems, and is intended to develop better imaging and also improve data links for the Protector. One of the biggest causes of drone crashes is loss of links with ground control.

The new contract reflects the increased dependence of the US and UK on drones over the last decade.

The plan is for the Protector to be armed with UK-made Brimstone 2 missiles and Paveway IV laser-guided bombs.

Fallon told the conference: “Britain faces ever-evolving threats and we must look at innovative solutions to stay ahead of our enemies. Doubling investment in our unmanned air fleet will substantially enhance both the intelligence gathering and firepower of the RAF.

“The UK’s security partnership with the US is the deepest and most advanced of any two nations on Earth; this programme is part of a further strengthening which will help keep Britain safe and secure.”

Tony Douglas, chief executive officer of the MoD’s defence equipment and support organisation, said: “Protector is a highly advanced system which will use world-beating technology to give us a decisive advantage on the battlefield. This contract signature is not only great news for our armed forces, but demonstrates how the strong relationship between UK defence and our allies helps to ensure best value for the taxpayer.”

