British Airways blamed a series of problems for Heathrow Terminal 5’s catastrophic first day, but other sources suggested a single issue – staffing.

BA chief executive Willie Walsh issued an apology, saying: “Problems developed that were not encountered during the extensive trials. There were problems in car parks, airport areas, computer glitches and the baggage system.”

A BA spokeswoman added: “There were a range of problems – system ­processes, the escalators and the transit ­system were not working, staff finding their way around and getting through security. There wasn’t just one issue.”

However, a spokeswoman for Heathrow operator BAA described problems with Terminal 5 as “relatively minor” and said: “The fundamental problem was to do with baggage processing. It was not to do with car park barriers or staff security checks.

“The hardware is working as it should. When baggage is not taken off the system it will shut down because it is overloaded.”

A spokeswoman for union Unite, which represents BA baggage handlers, said members had warned about inadequate training and familiarisation. “There was an over-reliance on systems management and not enough training,” she said.

Advantage business travel director Norman Gage said: “This was a people problem. BA has pared its staff to the bone so when it had a problem there were not enough people to sort it out.”