Flights cancelled on Day 2 at new Heathrow terminal

LONDON, March 28 (Reuters) - British Airways cancelled a fifth of its flights from Heathrow airport's cavernous new 4.3 billion pound ($8.63 billion) Terminal 5 on Friday as the chaos of its shambolic opening spilled into a second day.

The open-plan terminal is Britain's largest enclosed space, equivalent to the size of about 50 football pitches, and was touted as the answer to the delays passengers can face at the world's busiest international airport.

British Airways said 80 percent of flights from Terminal 5, including all long-haul flights, would operate on Friday and that customers could check in both hand and hold luggage.

Some stranded passengers spent the night in the gleaming terminal, reluctant to pay for nearby hotels even though the authorities had promised to reimburse them.

"I am very sorry that the problems have meant that some of our customers did not experience the true potential of this amazing new building," British Airways Chief Executive Willie Walsh said in a statement.

At least 33 short-haul flights were cancelled on Thursday and a new state-of-the-art baggage handling system ground to a halt, leaving only those with hand luggage able to fly. (Reporting by David Clarke, editing by Tim Castle)