Putting your computer to ‘sleep’ uses almost as much energy as leaving it on. Switching off saves energy immediately and helps slow global warming, a new exhibition reveals.

Along with the 90 million tonnes of edible fish caught annually, 20 million tonnes of unwanted fish, sea birds and other creatures are slaughtered, is another arresting fact produced by the National Maritime Museum.

They are opening a new environment gallery, Your Ocean, at their Greenwich establishment on 24 November.