The baggage system at the centre of the delays that have plagued Heathrow’s Terminal 5 since it opened last Friday was tested for half the time originally recommended by engineers.

It is understood that when the project was in its infancy, experts at airport operator BAA recommended that there should be between nine months and a year of “operational readiness” testing of the baggage system before the £4.3bn terminal five opened, rather than the six months that was actually carried out.

A source said: “The baggage system at T5 required a degree of automation never achieved before. It is a huge, great spaghetti of mechanical systems. We decided we needed a year of operational readiness, doing nothing else but running operations through it.”

During T5’s disastrous opening week more than 200 flights were cancelled and 20,000 pieces of luggage misplaced.

The failure of baggage handling operation has been cited as a major cause of T5’s operational problems.

It is understood that BAA approached logistics consultants for extra assistance in sorting out the issues.

Ian Booker, a specialist systems engineer on T5 during the nineties, said nine months had been discussed when BAA was planning its construction programme: “I remember suggesting nine months, but six months was what was agreed, and built into the programme.”

It is a huge, great spaghetti of mechanical systems

A source close to T5

Rob Stewart, construction director for BAA Capital Projects, the company’s design and construction arm, denied that a longer testing time than six months had ever been discussed.

He said: “The period in the construction programme for operational readiness was six months, from the day we put a spade in the ground. We have been trialling the building since 17 September, and the baggage system has been operating throughout that time.

“The building was ready to go. The impact of human factors has created most challenges.” He would not be drawn on whether BAA or BA staff were to blame.

He added: “Clearly, it’s very disappointing we didn’t get off to the glorious flying start we anticipated, but the key thing is there was nothing wrong with the building. We should not let this opening detract from the fact that we have raised the bar for construction and engineering in this country.”

It is also understood that at least 150 M&E workers are still on site at T5. Snagging work, including on some lifts, remains to be completed.