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
Judges in the European Court of Human Rights have rejected a plea from the parents of terminally-ill baby Charlie Gard to intervene.
A mum from Essex has launched a campaign to encourage young black women to stop altering their natural hair.
Arthur Simpson-Kent killed Sian Blake and their sons at their bungalow in Erith, south-east London.