BRITAIN is the land of the orderly queue, at least in theory. But the wait endured by people seeking to clear immigration at Heathrow, the world's busiest airport for international visitors, topped two-and-a-half hours at one point last week. Boris Johnson, London's mayor, and others complained that Britain's image was tarnished. Now immigration officials plan to stage a strike on May 10th. The chaos could overshadow the Olympic games, which begin on July 27th. Ensuring that undesirables are kept out of Britain but that wealthy businessmen and high-spending tourists are welcomed is a tricky balancing act, made harder by sheer numbers. Almost 70m people passed through Heathrow in the past year, 93% of whom were on international flights. Arrangements introduced in 2007 permitted certain checks to be skipped when queues at passport control become dangerously long. But controls were tightened again six months ago, following a row between the home secretary, Theresa May, and Brodie Clark, then head of Britain's border-control workforce, over the relaxation of immigration controls. What puzzles exhausted passengers arriving at Heathrow, however, is not the stringency of the immigration controls but the incompetence of the operation. Desks are unmanned, or close just as a planeload of people arrives. Fast-track channels are often anything but. Iris scanners - which operate in four of Heathrow's five terminals - frequently fail. Some officials deter people from using the "e-gates" intended to expedite arrivals, which read the electronic chips inside passports and open if the person's face matches the details held. Skytrax, a company which ranks travellers" experience of airports, places Heathrow well behind its rivals in the Netherlands and Germany. Willie Walsh, head of the International Airlines Group, the parent company of British Airways and two other airlines, says that Heathrow needs an overhaul, with more technology and better-deployed staff. Such reforms would come as budgets are being squeezed and staff shed: the Border Force is expected to contract by a fifth between now and 2015. The unhappiness is being shared with passengers: a row over raising the pension age has led to next week's strike. Hauled before Parliament to explain the mess, Damian Green, the immigration minister, promised a new central control room to monitor queues, mobile teams that could be dispatched to clear backlogs and a new rota to ensure that staff are on hand when needed. Ministers hope such measures - and recruiting temporary staff - will prevent chaos during the Olympics, when visitor numbers could spike. The standard policy of checking all passengers with roughly equal rigour, sharply reinstated following last year's row, could also be sensibly altered. Keith Vaz, who chairs the House of Commons" Home Affairs Committee, points out that passenger records can be transmitted to the destination airport far faster than people. More than 13m people who arrive at Heathrow each year come from an American airport, where they endure close interrogation and strict security standards. Using such information to identify those who need careful questioning by British officials, and those who do not, could help get the queues moving, and keep tempers cool.