Britain sent Royal Navy warships on Monday to rescue those stranded across the Channel by the volcanic ash cloud, and the aviation industry blasted European transport officials, claiming there was “no coordination and no leadership” in the crisis that shut down most European airports for a fifth day.

Eurocontrol, the air traffic agency in Brussels, said less than one-third of flights in Europe were taking off Monday — between 8,000 and 9,000 of the continent’s 28,000 scheduled flights.

Some smaller airports reopened Monday but authorities in Britain, France, Germany, and the Netherlands — home to four of Europe’s five largest airports — said their air space was still closed. Britain said it was keeping flight restrictions on through early Tuesday while Italy briefly lifted restrictions in the north then quickly closed down again after conditions worsened Monday.

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.