LONDON (Reuters) - A British chain of opticians saw publicity gold on Friday after Olympic officials blundered by showing the South Korean flag instead of North Korea's at a women's soccer match.

Opticians Specsavers took out adverts in national newspapers with the North Korean flag above the South Korean one and, written in Korean, a message suggesting the officials should have visited them for an eye test.

The company's regular tagline, used in commercials featuring embarrassing cases of mistaken identity, is 'Should have gone to Specsavers'.

The gaffe in Glasgow on Wednesday caused a diplomatic incident, with the North Koreans walking off the field and delaying the kick off by more than an hour.

Organizers LOCOG apologized and promised the mistake would not happen again.

(Reporting by Alan Baldwin, editing by Matt Falloon)