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
London mayor Sadiq Khan is "extremely worried" about knife crime as Met Police revealed there was an increase in stabbings in the capital.
Camden police have responded to reports of an unexploded World War Two bomb in Hampstead high Street.
AFC Wimbledon face Plymouth in the League Two play-off final at Wembley, with a place in League One at stake.