The new Flight-Plus licence may bring into the Atol system at most half the six million bookings assumed by the Department for Transport and probably fewer.

Research by TNS for Travel Weekly suggests no more than 8% of recent holiday bookings would qualify as Flight-Plus and possibly only 5% – between 2.91 million and 1.82 million in 2010.

TNS questioned more than 2,000 UK adults and found three in five had an overseas holiday in the last four years. It then asked how they booked their last holiday and found 42% bought a package holiday and 27% flight-only.

Just 22% booked separate holiday elements, but 14% did so with separate companies, meaning these sales would not fall under Flight-Plus.

Only 8% reported booking separate elements with a single company – 5% at the same time and 3% at different times. The former would constitute Flight-Plus bookings if involving a flight and accommodation. The latter would be Flight-Plus only if made on the same day or consecutive days.

However, many of these bookings would have been with airlines and outside Flight-Plus for the time being.

If we take 2010 as an example – when official figures show 36.4 million people took an overseas holiday – then the Flight-Plus market, including ‘airline holidays’, appears to number between 1.8 million (5%) and 2.9 million (8%) or a half to one-third of the DfT estimate.

The smaller figure is in line with private estimates by Thomas Cook and Tui Travel UK confirmed to Travel Weekly. The CAA suggests the number could be four to six million. David Moesli, deputy director of the CAA consumer protection group, said this week: “It will certainly be north of two million.”

CAA and DfT documents issued last week suggest the six million figure is based on an assumption that two million bookings would drop out of the Atol system over the next four years without reform.

The TNS survey found the highest rate of separate bookings among upper and middle-class holidaymakers, at 22%.

Package holidays were more popular among the less well-off and comprised 50% of bookings among those with teenaged children, adults aged 55 and over, and in the north.

Packages did not fall below 35% of bookings in any social class, age group or major region except London, where flight-only sales were most popular at 52% and packages just 15%.

Of course, consumers might believe they had a package holiday when they did not or that they were booking with separate companies when they were not.

Total Atol-protected sales in the year to March were 18.5 million, or 50% of the total.

The TNS research was conducted in November.