YouTube has launched an investigation after it was found to be suggesting paedophilic phrases in its search suggestions.

Several users reported that typing "how to have" into YouTube's search bar would prompt the suggestion "s*x with your kids" and "s*x in school".

"Earlier today our teams were alerted to this profoundly disturbing autocomplete result and we worked to quickly remove it as soon as we were made aware," a YouTube spokesman said, referring to the first result. "We are investigating this matter to determine what was behind the appearance of this autocompletion."

However, the second result - "how to have s*x in school" - continued to be shown on Monday.

The existence of the asterisk in the term "s*x" suggests it appeared as a result of a campaign to avoid YouTube's filters, which might have whitewashed the term "sex", and to deliberately skew the results. This could be achieved by entering search terms multiple times and tricking YouTube's search algorithm into thinking it was a popular request.