In his article, Mr Cameron says that action is needed now to “keep us safe for generations to come”.
“As the murders in Paris reminded us so starkly, Isil is not some remote problem thousands of miles away, it is a direct threat to our security,” he writes.
“So I want the British people to know they have a government that understands national security and that we will take whatever actions are necessary to keep our country safe.
“We cannot leave the burden and risk of protecting out country to others. Such action would be one key element of a comprehensive, long-term strategy to defeat Isil, in parallel with a major international effort to bring an end to the war in Syria.”
The government will announce plans to invest more than £178billion in military equipment over the next decade, including two new squadrons of Typhoon combat jets, 39 stealth fighters, nine “submarine hunting” planes and a new generation of drones.
The life of Britain’s fleets of Typhoons will be extended until 2040 Photo: Eddie Mulholland/The Telegraph
The new strike brigades will be able to respond to international threats to Britain miles away at short notice, with enough support to “sustain themselves in the field” and operate independently.
The government will also increase counter-terrorism funding by a third to £15billion, with new investments in detecting “high risk” passengers new border security measures to tackle weapons smuggling.
Spending on the special forces will rise by £2 billion. The major investments, unveiled in the strategic defence review, come as Mr Cameron prepares later this week to publish a seven-point dossier setting out the case for military intervention in Syria
ahead of a Commons vote which is expected before Christmas.
In his article
, the Prime Minister says: “Britain is fortunate to have some of the finest Armed Forces, counter-terrorism police and security services in the World.
“This Government will ensure they stay that way. Using our renewed economic strength we will equip them to defeat the terrorist threat and help keep us safe for generations to come.”
Barack Obama, the US President, on Sunday vowed to “destroy” Isil which he dismissed as a “bunch of killers with good social media”. He said that the West will not “succumb to fear” as he called on “every country” to send a signal that the “viciousness of a handful of killers does not stop the World from doing business”.
Jeremy Corbyn, the Labour leader, is poised to retreat on plans to bar his MPs from voting with their conscience on Syria in the face of a public rebellion by his shadow cabinet and up to 60 MPs.
Senior Labour MPs including Tom Watson, the deputy leader of the party, Hilary Benn, the shadow foreign secretary, and Maria Eagle, the shadow defence secretary, are increasingly convinced of the case for military intervention.
Mr Corbyn last week provoked fury within his party by questioning Britain’s shoot to kill policy in the event of a terror atack and suggesting the authorities should have arrested rather than killed Jihadi John.
In his article Mr Cameron accuses the Labour leader of failing to live in the real world. “This is not a time to equivocate about allowing our police to shoot a terrorist and save the lives of innocent people,” he says. “It is not a time to stand back and wish for another world where Jihadi John could somehow be arrested.”
He says that Britain is now the only major country in the World to commit to spending 2 per cent of national income on defence while meeting the UN target of spending 0.7 per cent on development.
He pledges to use Britain’s “renewed economic strength” to invest in defence and security as the World becomes “ever more dangerous and uncertain”.
He says that Britain will “refocus” its £11 billion foreign aid budget by committing half of it to supporting “fragile and broken states and regions”.
Army chiefs will re-organise troops to create two new rapid response strike brigades by 2025 which be able to deploy thousands of miles away at short notice.
The two brigades will be supported by 600 new Scout armoured vehicles,which are highly manoeuvrable and can travel at around 50mph.
It comes amid concern that the West has struggled to respond quickly enough to the speed of Russian aggression in Ukraine and conflict in the Middle East.
Mr Cameron will reverse the decision to axe nine Nimrod maritime patrol jets, which was one of the most controversial aspects of the 2010 spending review.
They will be replaced with nine new “submarine hunter” Boeing P8m aritime patrol aircraft, which are equipped with torpedoes, sonar buoys and a suite of sensors.
Britain has been repeatedly forced to call in help from allies to track Russian nuclear submarines which have strayed into the nation’s territorial waters.
The RAF will be given two new combat squadrons by taking planes out of storage and extending the life of the jets to 2040. Some of them will be fitted with missiles and bombs so they can take part in air strikes.
The new counter-terrorism funding will include upgraded border systems as well as the establishment of a National Digital Exploitation Service which will specialise in hacking seized phones, computers and other devices.