A luxury government jet sold to a US firm two years ago for less than €420,000 is now insured for $5m (€4.7m) and has recently flown from New York to Paris and Barbados.

Department of Defence officials will today defend the controversial sale of the Government jet for less than half its price, claiming that serious market problems meant the low cost was the only option available.

The State's spending watchdog has said the Government might have lost out on extra cash over the sale of the government jet.