Tomorrow is the best day to book the cheapest flights for this summer, according to new research.

Researchers at Which? Travel, who used data for millions of flights listed on Skyscanner in 2017 and 2018, found that 4 January is the best day to book the cheapest flights for the this year's summer holiday.

Which? found that for busy periods such as bank holidays, Christmas and Easter, the cheapest flights where available between three and four months in advance.

However for the school summer holidays, a peak travel time for families, the cheapest flights were on sale either six months ahead of departure, or just a week or two before.

On average, flights were 7 per cent cheaper than average when booked during these times, said Which?.

The consumer champion added that the low fares were likely to remain below the average price for around the next week.

The school summer holiday typically begins at the end of July and runs until the start of September.

Sardinia, Greece, Canada and Rome are some of The Independent's best family holiday picks this year.

Alternatively, to read where you should avoid this year, click here.

Read More