§ The Prime Minister
My right hon. Friend the Secretary of State for Defence is currently reviewing the estimate of cost of Trident and expects to make an announcement to Parliament shortly. The latest published estimate for the Trident programme based on the use of the Trident D5 missile, is £8,729 million at an exchange rate of $1.53 = £1. The original estimate for Trident given in 1980 and based on the Trident C4 missile, was £4,500 million to £5,000 million. Of the increase in cost, about £1.25 billion relates to exchange rate variations.