The Netherlands is to take part in initial operational test and evaluation (IOT&E) of the Joint Strike Fighter alongside the USA and the UK, and will provide two Lockheed Martin F-35As for the multinational test force.

The Dutch defence ministry has informed parliament of its decision to take part in IOT&E and to make a 10% downpayment on two F-35s this year, but it will make a final decision on buying the aircraft in 2009. The F-35s will be delivered in 2011 and 2012, with IOT&E from 2011-13.

The Royal Netherlands Air Force plans to buy 85 conventional take-off and landing F-35s to replace its Lockheed F-16s, with the nation holding Level 2 status on the programme's system development and demonstration phase.

The Dutch have planned to take part in F-35 testing since signing a memorandum of understanding on JSF production, sustainment and follow-on development in February 2006, but the government says negotiations took longer than expected.

Justifying its decision to join the multinational test programme - a commitment worth €275 million ($422 million) - the government says it will be quicker and cheaper than conducting a national IOT&E programme, which it estimates, would require 10 aircraft, an additional €200 million to rent airspace in Australia or the USA, and would delay the air force's initial operational capability by two years until 2018.

The Netherlands says it will re-examine the business case for the JSF before deciding whether to buy the two test aircraft early next year.

A slow-down in US procurement has pushed up the cost of its Replace F-16 programme, the government says. In 2006, the Netherlands estimated the cost of 85 F-35s at €5.5 billion, but the government says this has now risen to almost €5.67 billion.

Italy also has an option to join the IOT&E programme with two CTOL F-35As, but political developments there may stop it signing an MoU in the short term.