A charity is hoping to harness the power of Twitter by sending out a new appeal for a missing child every 30 minutes on Tuesday.
The Big Tweet for Missing Children will highlight some of the 100,000 youngsters who go missing in the UK every year.
Kerry Needham, whose 21-month-old son Ben went missing 19 years ago, said: "Every morning and every night I look at his picture and it gives me strength. I am his mum and I will never give up hope."
The 24-hour event on Twitter, which will use #IMCD for International Missing Children's Day, encourages users of the popular micro-blogging site to retweet the messages sent by the Missing People charity, increasing the number of people who see the appeals.
TV host Lorraine Kelly, a patron of the charity, backed the campaign, saying: "As a mum myself I can't imagine anything worse."
Anyone wishing to join the campaign should follow @missingpeople on the site.