Unreliable Equipment 62. Mr. John Hughes To ask the Secretary of State for Defence what assessment he has made of the annual cost of maintaining unreliable defence equipment. Mr. Skinner To ask the Secretary of State for Defence what assessment he has made of the annual cost of maintaining unreliable defence equipment. Mr. David Marshall To ask the Secretary of State for Defence what assessment he has made of the annual cost of maintaining unreliable defence equipment. Mr. Neubert At a very broad estimate, unreliability adds £1 billion a year to the cost of maintaining the services' equipment.