During the summit in Warsaw, Cameron will announce that hundreds more British troops are to be deployed to eastern Europe as part of a show of strength by Nato in the face of an increasingly assertive Russia.
The UK will send a 500-member battalion to Estonia, with a further company of 150 troops to be stationed in Poland “on an enduring basis”.
From next year, Britain takes over the leadership of the Nato very high readiness joint taskforce, with 3,000 troops in the UK and Germany on standby to move at five days’ notice.
Ahead of the trip, Cameron said: “This summit is a chance for us to reiterate our strong support for Ukraine and our other Eastern allies to deter Russian aggression.
“Actions speak louder than words and the UK is proud to be taking the lead role, deploying troops across eastern Europe. It is yet another example of the UK leading in Nato, as underlined by our pledge to spend 2% of GDP on defence for the rest of this decade.
“With a battalion commitment to Estonia as part of Nato’s enhanced forward presence, a company group in Poland and UK command of the very high readiness taskforce – which will involve committing 3,000 British troops – as well as our continued commitment to Baltic air patrols throughout 2017, Britain is clearly demonstrating its crucial contribution to Nato.”
A Whitehall official said: “In terms of what we are going to be announcing or committing to at Nato, it’ll be back to the issue of our strength in the world and about our ability to use our muscle to protect our allies and their own security.”
Although he is stepping down as prime minister in September, Cameron is expected to offer assurances to other Nato leaders that Brexit will not affect the UK’s ability to keep up its military capabilities.
The official continued: “He will confirm that we will be steadfast in our commitment to Nato and that we will back that up with boots on the ground, as we stand shoulder to shoulder with our allies in the face of growing threats to our borders.
“The crucial role that we play in Nato will be confirmed by the PM at this summit with details of a three-pronged deployment of British troops. This demonstrates the reach of our military power, an influence that is undiminished.”
It was the first chance for Nato members to assess the outcome of the 2014 Wales summit, the official said.
“This comes at a critical time for the alliance. We’re facing threats to the east from Russia, and south, with the Middle East and north Africa in turmoil, with obviously consequences for our security,” they added.
Cameron’s trip will be the first time that he has used the plane, which was overhauled at a cost of £10m. It will also be available to senior ministers and members of the royal family for official visits.
The aircraft has a luxury section at the front for the prime minister and a less exclusive area at the back for the accompanying press pack and advisers.
The government insists that having a dedicated plane will save money in the long term over chartering transport for each trip abroad.
This article was written by Rowena Mason and Harrison Jones, for theguardian.com on Friday 8th July 2016 00.01 Europe/Londonguardian.co.uk © Guardian News and Media Limited 2010