A lack of staff to handle peak periods and job cuts have caused passenger delays at Heathrow, a report says.
Chief Inspector of Borders and Immigration John Vine said the resources did not match passenger demand. This was "damaging the ability of border staff to maintain effective and efficient controls".
The report on the UK Border Agency and the Border Force was based on an inspection of Terminal 3 immigration between August and November last year.
Inspectors said new team structures, rosters and shift patterns had come as border staff numbers at Terminal 3 fell by 15% from 322 to 277 in the 12 months to last August.
The changes were "simply far too much organisational change during the busiest time of the year".
The report found queue targets for passengers from outside the European Economic Area were breached 62 times between September 18-30 last year, with the longest wait hitting two hours and 15 minutes.
Vine said: "I found that recent organisational changes such as the introduction of team-based working, a new shift working system and the amalgamation of immigration and customs roles had suffered from a lack of effective planning.
"Resources were not matched to demand, management oversight and assurance was lacking in many areas and staff were not always properly trained to undertake their duties.
"This was far too much organisational change during Heathrow's busiest time of the year.
"I remain concerned that this lack of planning has affected the agency's ability to maintain an effective and efficient border control."
Immigration minister Damian Green said: "This report covers the period before the Border Force was split from the UK Border Agency and since then we have taken action to tackle these issues.
"We now have more staff at the border during peak times, greater flexibility to man immigration and customs controls, clearer guidance for staff on when vital checks are required and a national training programme with more emphasis on mentoring.
"A culture change is under way to make Border Force an organisation that effectively tackles illegal immigration, protects the UK from terrorism and detects crimes like drug trafficking and weapon smuggling."
This is a community-moderated forum.
All post are the individual views of the respective commenter and are not the expressed views of Travel Weekly.
By posting your comments you agree to accept our Terms & Conditions.