British warplanes are awaiting orders to launch missile attacks against Islamic State after Parliament backed military action in Iraq, BBC reported.
Six Tornado G4 fighters have been based in Cyprus since August but so far have only been used for reconnaissance.
The bombers are expected to lead any British operations targeting IS.
MPs voted overwhelmingly for the UK to join the US-led air strikes in Iraq. Britain has stopped short of extending its support to operations in Syria.
After a seven-hour debate on Friday, MPs from all three main Westminster parties voted for military action by 524 votes to 43.
As well as the Tornados at the British Akrotiri base in Cyprus, the RAF also has a Rivet Joint spy plane - successor to the Nimrod - in the region.
Defence Secretary Michael Fallon said "intensified surveillance" would identify "convoys" of IS fighters.
But speaking to BBC's Newsnight, he warned the campaign would be "long and drawn out".
"You should not expect immediate shock and awe - a wave of fighters or bombers taking off," he said.
"It isn't that kind of campaign."
The aim in Iraq was to "push" Isil out of the country and improve its security situation within its "existing borders", he told the programme.
IS - sometimes referred to Isis or Isil - has claimed the Syrian city of Raqqa as the capital of its self-declared caliphate.
It controls large swathes of Syria and Iraq after rapid advances through the region earlier in the summer.
The US has been carrying out missile strikes against IS targets in northern Iraq since mid-August and American raids over Syria are now "near continuous", an official told the AFP news agency on Friday.
The Americans have said IS is being damaged by the air operations but will not be defeated without ground combat.
Downing Street has said it would seek separate Parliamentary approval for the extension of air strikes to Syria but reserved the right to act without consulting MPs in the event of a humanitarian emergency.
During the debate Mr Cameron said there was "no legal barrier" to military action in Syria, but he acknowledged there was no consensus among MPs for such a move.
Mr Fallon reiterated that there was already a "strong legal case" for air strikes in Syria, adding: "This is a battle against Isil that can only be won in both countries."
The jihadi group has been condemned in the West for its persecution of religious minorities and brutal tactics including beheadings and crucifixions.
Two British hostages are thought to be being held by IS, journalist John Cantlie and taxi driver Alan Henning.
But the defence secretary said the UK would not allow "overall strategic decisions" to be affected by the plight of the men.
"Both those lives very sadly are in danger anyway," Mr Fallon said.
Jets from Saudi Arabia and the United Arab Emirates have acted alongside the US, and America says more than 40 countries have offered to join the anti-IS coalition.
French fighter jets are already taking part in strikes in Iraq and Belgium and Denmark are also sending planes.
On Friday some 23 Labour MPs voted against air strikes, as did six Conservatives, one Liberal Democrat, two Plaid Cymru MPs and five Scottish National Party MPs.
They were joined in the no lobby by Green MP Caroline Lucas, three Social Democratic and Labour party MPs and Respect MP George Galloway. Two MPs acted as no tellers during the vote, Labour's Jeremy Corbyn and the SNP's Pete Wishart.
Prime Minister David Cameron had said military intervention was "morally justified" to combat a "brutal terrorist organisation" and was clearly lawful.
Labour leader Ed Miliband also backed intervention, telling MPs inaction would lead to "more killing" in Iraq.
Liberal Democrat leader Nick Clegg said it was "impossible to reason with" IS
Speaking after the vote on Friday, Labour MP John McDonnell warned the 2003 war in Iraq was one of the reasons for the rise of IS and said the UK seemed to be "making the same mistakes" again.