LONDON, England (AFP) — Border staff drafted in to cope with the influx of visitors to Britain for the Olympic Games may lack proper training and immigration experience, an independent watchdog warned yesterday.

John Vine, chief inspector of borders and immigration, said that extra staff brought in to ease congestion at London's Heathrow Airport, the main gateway to the Games, were taking longer to process visitors despite asking fewer questions.

According to Vine's report, some staff "remained concerned about the potential risks of employing staff on the immigration control who had received only basic training and who had no immigration background/experience".

"Staff also expressed concerns about similar problems recurring after the Olympics, if resources were not sufficient to meet the increasing passenger flows coming through Heathrow," he added.

UK Border Force, the interior ministry agency responsible for protection of the country's borders, is also re-hiring former employees as it prepares to deal with an expected 100,000-a-day spike in arrivals, Vine revealed.

Around 500 extra staff have been brought in to ease immigration queues, but an inspection in April found that the new officers "appeared less confident when processing passengers".

"This meant they often took longer to process them and asked fewer probing questions," the inspectors said.

"We felt this affected how efficiently and effectively Border Force was able to progress passengers through the terminal."

Vine stressed that it was vital all plans were "resourced appropriately to deliver an efficient and effective service".

A Border Force spokeswoman said the report highlighted "real improvements at Heathrow".

"John Vine acknowledges the positive addition of hundreds of extra staff deployed to meet demand, the creation of a central control room to manage resources and on going recruitment of more border officers," she said.

British airport operator BAA admitted last week that immigration queues at Heathrow had recently become "unacceptably long".

Some passengers were forced to wait for two and a half hours for passport checks at the west London airport, which will welcome around 80 per cent of the athletes, officials, fans and media coming for the Games.

Hours-long immigration queues at the airport, the world's busiest in terms of international passenger traffic, caused major embarrassment to the British government in May, just weeks before the Olympic opening ceremony on July 27.

With thousands of athletes due to land at Heathrow over the next three weeks, there are fears that the Home Office, or interior ministry — which is responsible for immigration — will not be able to cope with the traffic.

Half-mile queues at Heathrow's Terminal 4 were reported last month.

Keith Vaz, Labour chairman of the Commons Home Affairs Select Committee, said he was "deeply concerned" that the Border Force staff being placed at immigration desks lacked the proper training.

The watchdog report was released the day after the government confirmed that the British army will supply extra troops to guard the Olympic Games over fears that the private security firm contracted to do so will not be able to provide sufficient trained personnel.