Ryanair has warned of gloomy profit prospects after the budget airline had lower than expected airfares over winter.

The Irish carrier lowered its full-year post-tax profit guidance from between 1.1 billion euros - £966 million - and 1.2bn euros - £1bn - to a new range of 1bn euros - £878m - and 1.1bn euros.

Ryanair said that winter fares are expected to fall seven per cent, a much bigger drop than the previously guided fall of 2%.

It booked profit of 1.45bn euros, or £1.2bn, last year, and the downgrade represents the second warning in quick succession.

Read more: Kick lines up new deal as momentum builds

The airline said in October that profits would be knocked by a spate of crew strikes and rising fuel prices.

Ryanair boss Michael O’Leary also warned that he cannot rule out further downgrades to profit guidance.

The firm opened more new routes in Edinburgh after it closed its base at the airport and cut the number of routes there from 23 to three, although Glasgow later won back four routes last year.

The Herald: Ryanair’s chief executive Michael O’Leary (PA)

Mr O'Leary, above, said: “There is short haul over-capacity in Europe this winter, but Ryanair continues to pursue our price passive/load factor active strategy to the benefit of our customers who are enjoying record lower air fares.

“While we have reasonable visibility over forward quarter four bookings, we cannot rule out further cuts to air fares and/or slightly lower full-year guidance if there are unexpected Brexit or security developments which adversely impact yields between now and the end of March.”

Read more: Hotelier finds lure of family firm too strong to stay away

However, the firm also expects stronger traffic growth of 9% to 142 million and stronger ancillary sales as more customers choose lower cost optional services.

Mr O’Leary said: “We believe this lower fare environment will continue to shake out more loss making competitors, with Wow, Flybe, and reportedly Germania for example, all currently for sale.”

Ryanair will release its third quarter results on February 4.