Staff at Heathrow’s Border Force need more training to avoid lengthy queues and potential security lapses during the Olympics, an independent report has warned.

The findings of the independent Chief Inspector of Borders and Immigration, John Vine, came despite extra border officers being drafted in to plug service gaps and provide support.

Vine revisited the airport to assess how well his recommendations to improve border service delivery had been implemented.

However, he found that secondary detection staff drafted in to work on the primary control to ease congestion often processed passengers “less quickly and asked fewer questions”.

“We recommend that Border Force must ensure that officers from the secondary detection area receive the necessary support and training to carry out immigration work to the same standards as staff with an immigration background,” Vine said in his latest report.

Vine also found that forgery detection training “was not being delivered on a regular basis (at least annually) to refresh and update skills among staff working at the Primary Control Point”. This led to inconsistencies between Terminals 3 and 4 in how often forgery detection equipment was used.

“We believe that Border Force needs to undertake further work [on training] to ensure that these two issues are not a contributory factor to the significant variance in forgery- detections between the two terminals,” the report.

However, the report did acknowledge that plans to ensure airport immigration operates effectively during the London 2012 Games were in place.

The Border Force said it will re-employ former immigration staff, ensure all ‘new’ staff have basic training and access to mentors as well as restricting annual leave for current employees.

“However, 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,” the report added.

Staff warned Vine that training and staffing problems could recur after the Olympics, if resources were not sufficient to meet the increasing passenger flows coming through Heathrow.

Responding to the report, immigration minister Damian Green said: "There are always places where you can improve and that is what we are doing.

"April was a bad month. We have put more people in since then, progressively ramping up the numbers and during the Olympics 300 officers will be on duty at Heathrow."

A Border Force spokesperson said: “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.”