A PCS Union spokesman said:
The issues of the last few days has brought to the public's attention what we have said for a long time, that ministers can't cut staff and expect to run the same service - not just on passport controls at Heathrow, but right across UKBA.
Clearly, the cuts already made have had a major impact and further cuts planned every year until 2015 will make the situation even worse.
More top news
Builders working on a residential and hotel scheme in Stratford City rescued a duckling after it was separated from the rest of its family.
British astronaut Tim Peake takes part in a test to see how a Mars rover handles when it's controlled from further away.
Jack Susianta, a 17-year-old student, died on July 29 2015 after jumping into the River Lee in east London.