Monarch Airlines, a British tour company that operates cheap vacation flights to European destinations, canceled its order for six Boeing 787 Dreamliners Tuesday.

The order was worth US$916 million at list prices when announced in 2006, but after standard discounts its estimated real value is US$600 million, based on data from market valuation firm Avitas.

The cancelation reduces the Dreamliner order book to 821 aircraft.

Last year, Boeing selected Monarch as a partner in the UK to perform maintenance and repair of 787s at its London and Manchester bases as part of the GoldCare service to support carriers flying the Dreamliner.

In a statement, Monarch said the order cancelation would not affect that engineering support agreement.