Reuters, London :The British government is preparing the ground to join the United States in launching air strikes against Islamic State in Iraq, but is moving cautiously to ensure it avoids a parliamentary defeat and acts as part of a regional coalition.Britain was quick to join US military action in Afghanistan and Iraq a decade ago. But a war-weary public and parliament’s rejection last year of air strikes on Syria have made Prime Minister David Cameron wary.He has also had to prioritise Scotland’s independence vote on Thursday over possible action.This time, people with direct knowledge of the government’s thinking say the plan is to move slowly, to woo parliament, and to only take a final decision to join air strikes once an international coalition has been formed and the Iraqi and Kurdish authorities are onboard.”Sometimes you deliver a bigger punch, and you deliver a more fatal blow against ISIL (IS) by getting all the components right before you do so,” Deputy Prime Minister Nick Clegg, the leader of the Liberal Democrats, the junior partner in Cameron’s coalition, said on Wednesday. Cameron, who has said he backs US air strikes on IS, is expected to discuss plans to tackle the issue during the United Nations general assembly next week in New York, but his spokesman has played down expectations of an announcement.”The UN meetings, and meetings around that, are a part of it but it’s a strategy over a significant period of time,” the spokesman told reporters earlier this week.Britain, a staunch US ally, is expected to take its lead from Washington which has so far limited itself to conducting defensive rather than offensive air strikes against ISIS while it assembles a coalition of regional powers to try to confer greater legitimacy on its struggle against the militant group.A YouGov opinion poll on Wednesday showed voters’ approval for British involvement in air strikes against IS had risen to 25 per cent, up 3 points in 11 days.A few months ago, the British government was not actively considering air strikes. But the beheading of a British aid worker by an IS militant with a British accent has highlighted the danger the group poses to Britain’s domestic security.Faced with the rise of IS, Britain has so far confined itself to delivering humanitarian aid, carrying out surveillance, arming Kurdish forces who are fighting IS militants, and promising training in Iraq.But lawmakers say politicians loyal to Cameron have been canvassing opinion in parliament on air strikes and that a consensus has emerged that a majority would vote to back British action against IS in Iraq if Baghdad asked for help and it was part of a wider regional effort.