Do I need to avoid barley malt extract?

Yes, barley malt extract contains gluten and should be avoided by anyone following a gluten free diet. However, some products contain 'gluten free barley', which means the gluten has been removed or the barley is used in very tiny amounts that are safe to consume (less than 20ppm) but these products must specifically state gluten free on the packaging. You'll find gluten free barley in products like gluten free beer or Branston pickle. Always check the label. Read more about barley malt extract here.