Britain sent Royal Navy warships on Monday to rescue those stranded across the Channel by the volcanic ash cloud. Prime Minister Gordon Brown said the aircraft carrier HMS Ark Royal and assault ship HMS Ocean would be sent across the English Channel. A third ship is being spent to Spain to pick up soldiers trying to get back to Britain after a tour of duty in Afghanistan."I expect Ocean to be in the Channel today. I expect the Ark Royal to moving towards the Channel later," Brown said after a meeting of the government's emergency committee, known as COBRA.Spain is offering landing slots to planes originally due to fly to European airports now shut because of the ash cloud, Spanish infrastructure miinister Jose Blanco said in a radio interview. This applies in particular to aircraft trying to bring Britons home from Asia, Latin America and North America.Prime Minister Jose Luis Rodriguez Zapatero and his British counterpart, Brown, agreed on the arrangement in a telephone conversation Sunday night, Zapatero's office said.