Dundee University has had to explain itself to a class of primary schoolchildren after ten-year-old Fergus Davidson wrote to principal Sir Alan Langlands complaining about the lights being on at night in the Wellcome Trust Biocentre. Master Davidson, who spotted this after a trip to see An Inconvenient Truth , Al Gore's documentary on global warming, asked Sir Alan to tell the researchers to switch the lights off when they left. Sir Alan explained that staff often worked late, adding that Dundee generated its own electricity from a combined heat and power plant. But he invited pupils to design posters to encourage staff to save energy.