The Government has promised action to deal with queues at Heathrow but blamed the rain for recent troubles and insisted claims of two-hour long waiting times were a "wild" exaggeration.
Immigration Minister Damian Green launched a robust defence of performance at the UK's busiest airport as London Mayor Boris Johnson joined mounting criticism.
Mr Johnson said visitors were being given "a terrible impression of the UK" and called for action to halt the vital transport hub "gaining such a poor reputation".
Despite efforts by border chiefs to prevent passengers taking pictures of queues, social media sites were full over the weekend with complaints about excessive waiting times.
The queues at Heathrow have been notoriously long in the last few days
Addressing MPs, the minister said the "vast majority" of passengers were processed quickly and that it was important not in any way to compromise border security.
The queues at Heathrow Terminal 5 on Thursday night at about 11pm
Despite targets being missed on occasion, 99 per cent of UK and other EU nationals got through within the 25-minute maximum and 96 per cent of the rest inside a 45-minute limit.
And the longest recorded wait was 90 minutes, he added – hitting out at "wild" reports of much longer delays but admitting: "These times are too long.
"Over the weekend there were some breaches of acceptable waiting times.
"This was caused mainly by the severe weather leading to flight diversions and changing flight schedules and the bunching of arrivals.
"Our information shows that queuing times bore no resemblance to the more wild suggestions."
