I'm not sure why the Wikipedia page dramatically disagrees with the UK's own stats.
The WHO explanation is here: https://www.who.int/data/gho/indicator-metadata-registry/imr... and their data is here: http://apps.who.int/gho/data/node.main.MHSUICIDEASDR?lang=en
The WHO explanation is here: https://www.who.int/data/gho/indicator-metadata-registry/imr... and their data is here: http://apps.who.int/gho/data/node.main.MHSUICIDEASDR?lang=en