Delta Air Lines will complete the refit of its business cabin to offer lie-flat beds on all flights out of Heathrow from September.

The seats are already available on Delta flights from Heathrow to New York JFK, Atlanta and Detroit, and will be installed on services to Minneapolis next month.

The refit of the business elite cabin includes direct access to the aisle from all seats, on-demand entertainment and other enhancements, and comes as British Airways considers reducing the number of business-class seats on some of its services, because of the downturn in premium traffic.

Delta – the leading US partner of Air France-KLM – will have 40 or 43 lie-flat beds available on flights, depending on the aircraft.