Thomas Cook’s retail arm has admitted making errors in an online competition which prevented people being able to enter a prize draw.

The admission came after a consumer complained to the advertising watchdog in June about not being able to submit a video to enter a competition on Twitter to win a £5,000 holiday gift card.

Thomas Cook Retail said it was committed to ensuring that the situation did not happen again by making sure links were fully working before promotions went live, and that the relevant teams were fully briefed on the rules in order to avoid incorrect information being provided.

The company told the Advertising Standards Authority that it “recognised that there were parts of the delivery of the prize promotion which did not run smoothly and regrettably errors were made”.

The ASA banned the advert from appearing again in its current form.

It said that “because the tweet did not include a closing date for submission of entries made via Twitter, did not have an operational link to the full T&Cs [terms and conditions], or make sufficiently clear that two closing dates applied to the prize promotion which depended on the method of entry chosen, we considered that the advertised promotion had not been dealt fairly and honourably with participants and concluded it breached the CAP [advertising] Code”.

In a ruling published today, the ASA said: “We told Thomas Cook that their future prize promotions must include an operational link to the full T&Cs the closing date for submitted entries and make sufficiently clear whether the closing date varied according to the method of entry chosen.”