The emphasis on first-class travel has switched away from the in-flight office to providing the perfect environment for a decent night's sleep.

Passengers are given steeply reclining seats with cotton sheets, pillows and duvets, as well as loose-fitting track suit-style pyjamas.

While extravagant five-course silver service dinners are still available, a choice of lighter, more digestible meals has been added to the menu for late night eating.

Cabin lights are dimmed almost throughout the trip and in-flight announcements are kept to a minimum.

When you are ready to call it a day, ''good-night cookies'' and mugs of bedtime hot chocolate are available on request.

Should you choose to snooze through breakfast, first-class passengers can dine, shower and have their clothes ironed at BA's new arrivals lounge at Heathrow Airport before heading into the city for the day.

The sleeper service concept was first pioneered by BA in January last year on its short night flights from New York and Boston to Heathrow.

It quickly reversed falling passenger numbers and gained market share.

First-class passenger load factors on BA's north Atlantic routes have gone up by 14 per cent since its launch.

Sleeper services have since been introduced on nearly all BA's night flights around the world lasting under nine hours that depart after 7 pm.

BA had no intention to extend the service to ultra-long-haul night flights, like its 141/2-hour London-Hong Kong service, until passenger demand persuaded the airline's management to change its mind.

David Charlton, BA's group brands manager for long-haul, said: ''Hong Kong is a trial for us to see how our sleeper service can be adapted for longer routes.

''If it works on the Hong Kong route, we could implement it right around the world.'' BA chose Hong Kong to try out its sleeper service partly because it has one of the highest quotas of first-class frequent fliers in the world, but also because it is about to face stiff new competition on the route.

Its arch rival, Virgin Atlantic Airways, which has been quick to adopt some of BA's sleeper-style gimmicks, will begin flying direct daily flights from London to the territory on February 22, breaking BA's and Cathay Pacific Airways' long-held duopoly ondirect services between the two cities.

In 1988 BA was the first airline to launch a dedicated business class service. Around 30 airlines have since responded by revamping what they offer to business class travellers.

To date, only United Airlines and Virgin have reacted to BA's sleeper service. It may not be too long before this too is the norm.