Early next month, ministers in Britain are expected to give the final go-ahead for two new £4bn aircraft carriers for the Royal Navy. The 65,000 tonne ships will be the most powerful ever to sail in the navy but there is growing concern that delays to the Joint Strike Fighter (JSF) programme in the US mean they will be setting out to sea without their intended aircraft.

The first of the navy's two new carriers is due to enter service in 2014. The government had planned to operate the JSF from the ships. However, it emerged this year the navy would initially have to operate the latest version of the Harrier jump jet, developed decades ago.