RYANAIR is to cancel an extra 18,000 flights in a move that will hit 400,000 customers as the fallout from the airline's mismanagement of pilot leave intensifies.

The Irish carrier said that as part of efforts to end a wave of cancellations that has already seen 2,000 flights grounded, it will fly 25 less aircraft between November and March.

The firm has been forced into the cancellations after miscalculating pilot leave.

Taking more flights out of service means that Ryanair will be able to "roster all of the extra pilot leave necessary" in October, November and December, the budget airline said.

As a result, 34 routes are suspended for the winter season from November to March 2018.

They include several popular routes used by British travellers, including Newcastle to Faro and Newcastle to Gdansk, London Stansted to Edinburgh and Glasgow, Gatwick to Belfast and Glasgow to Las Palmas.

The move will add to mounting anger over Ryanair, which has come under heavy fire after recently shelving up to 50 flights every day for six weeks.

Boss Michael O'Leary has blamed the move on mismanagement of pilots' annual leave, leading to the over-allocation of blocks of holidays.

The flight cancellations has so far cost the airline around 25 million euro.

Ryanair said the latest step will "eliminate all risk of further flight cancellations" and remove the risk of similar problems recurring next year.

The firm also plans to roll out a series of low fare seat sales for winter 2017 as it is "confident that there will be no further roster related cancellations".

It argued less than 1% of the 50 million customers Ryanair will carry this winter are impacted and all affected passengers have received an email alerting them and offering alternative flights or full refunds.

They have also received a 40 euro travel voucher.

Mr O'Leary said in a statement: "We sincerely apologise to those customers who have been affected by last week's flight cancellations, or these sensible schedule changes announced today.

"From today, there will be no more rostering related flight cancellations this winter or in summer 2018.

"Slower growth this winter will create lots of spare aircraft and crews which will allow us to manage the exceptional volumes of annual leave we committed to delivering in the nine months to December 2017. We will start a new 12 month leave period on the 1st of Jan 2018 in full compliance with EU regulations and the IAA's requirements."

The firm also said that it has scrapped plans to bid for bankrupt Italian airline Alitalia in order to "focus on repairing this rostering problem this winter".

"Ryanair will eliminate all management distractions starting with its interest in Alitalia," the group said.

Ryanair's decision to ground 25 aircraft between November and March will mean 34 routes are suspended for the winter season.

Here is a list of the routes being suspended:

:: Bucharest - Palermo

:: Chania - Athens

:: Chania - Pafos

:: Chania - Thessaloniki

:: Cologne - Berlin (SXF)

:: Edinburgh - Szczecin

:: Glasgow - Las Palmas

:: Hamburg - Edinburgh

:: Hamburg - Katowice

:: Hamburg - Oslo (TRF)

:: Hamburg - Thessaloniki

:: Hamburg - Venice (TSF)

:: London (LGW) - Belfast

:: London (STN) - Edinburgh

:: London (STN) - Glasgow

:: Newcastle - Faro

:: Newcastle - Gdansk

:: Sofia - Castellon

:: Sofia - Memmingen

:: Sofia - Pisa

:: Sofia - Stockholm (NYO)

:: Sofia - Venice (TSF)

:: Thessaloniki - Bratislava

:: Thessaloniki - Paris BVA

:: Thessaloniki - Warsaw (WMI)

:: Trapani - Baden Baden

:: Trapani - Frankfurt (HHN)

:: Trapani - Genoa

:: Trapani - Krakow

:: Trapani - Parma

:: Trapani - Rome FIU

:: Trapani - Trieste

:: Wroclaw - Warsaw

:: Gdansk - Warsaw