Monarch Airlines has gone bust and is cancelling 300,000 bookings

Aircraft of British carrier Monarch is parked on the apron at Larnaca airport, Cyprus November 7, 2015. (REUTERS/Yiannis Kourtoglou)

LONDON — Monarch Airlines has gone into administration after failing to secure its financial future over the weekend.

Monarch, one of the UK's oldest airlines, announced it was ceasing trading on Sunday. It is the largest ever administration of a UK airline.

All future flights have been immediately cancelled, affecting an estimated 300,000 bookings.

110,000 passengers are now stranded abroad as a result of Monarch's administration and the UK's Civil Aviation Authority (CAA) is stepping in to put on emergency flights to bring people home — the biggest post-war time repatriation effort in Britain.

Rumours of financial trouble at Monarch first surfaced in September last year but the airline strongly denied it was in trouble. The airline received a funding injection shortly after but has failed to turn things around. Monarch lost £291 million in the year to October 2016.

Monarch, based in Luton, was founded in 1967 and ran flights to the Mediterranean.