According to The Times, three of the British Navy's four Vanguard-class SSBNs are now at sea at the same time, an unusual situation not seen for more than five years. At least one of the submarines carries Trident nuclear-tipped ballistic missiles, while the other two are expected to undergo sea trials or be ready for operational service. A fourth submarine, Conductor, is undergoing maintenance at Davenport. Navy sources called the situation unusual but suggested it reflected an improvement in the Royal Navy's operational readiness rather than a signal aimed at Russia.