British Airways is offloading thousands of suitcases to a warehouse in Italy in an attempt to cope with the backlog of 19,000 bags that failed to get on to flights amid the chaos at Terminal Five.

The airline said more than 400 "volunteers" – workers from other parts of the company – were helping to transport the mountain of luggage to a courier firm in Milan after T5's supposed state-of-the-art automated baggage system was unable to process delayed suitcases.

From Milan bags will be sorted and either driven or flown to their owners.

"Delayed bags must undergo enhanced levels of security screening," a BA spokeswoman said. "Much of this must be done manually rather than using the automated baggage systems.

"Although most of the delayed bags will be sorted and reflighted at Heathrow, it is quicker for bags with European mainland addresses to go to Milan for sorting and onward transport than to wait for flights leaving Heathrow."

She said using the Milan-based courier firm was standard practice for BA when dealing with a baggage backlog.

Although the bags take 24 hours to reach Milan by lorry, it can be quicker than by air because bags travelling by road do not have to be screened.

However, bags travelling to people on holiday are likely to reach the correct hotels only after the owners have flown home. They may then have to be returned to Milan to be sorted again.

Bags belonging to passengers on domestic flights are being driven to Manchester and Scotland, where they will be sorted and dispatched to their owners.

BA said travellers whose bags were lost could claim for "immediate expenses" but did not define what that covered or say how much it would reimburse.

Passengers faced more misery yesterday as BA axed 50 more flights from T5. The airline said 32 flights would be affected today, bringing the total number of cancellations since the terminal opened to 430. However, BA said it expected 92% of flights to be operating on Thursday.