Vodafone has revealed a Champions League advertising campaign featuring beer-belly-shaking football fan fairies, in a bid to lock-in customers across Europe.

The mobile phone group's TV campaign will feature "magical messengers", or imp-sized fans, who fly out of football stadiums to deliver match news to supporters who don't get to see the game.

Vodafone is struggling to hold on to subscribers across fiercely competitive markets and knows a three-year sponsorship deal with Uefa needs to do more than just push its brand up the best-known board. The deal includes content rights, as well as broadcasting airtime, and means it can offer subscribers match reports and goal alerts from the biggest tournament in club football.

It believes that if fans can download footage wherever they are, it will "entangle" them so they do not defect when better tariffs come along. "When we get customers entangled, they become more loyal," said Vodafone's global director of brand and customer experience, David Wheldon. "It would be wrong to say entanglement is the cure to churn, but it really does make a remarkable difference."

"Churn", or the proportion of customers defecting, is a key concern as markets become increasingly saturated. Subscriber numbers have been hard hit in Germany, its biggest market, while in the UK, its customer base fell by 119,000 in the most recent quarter.

But it hopes the Champions League sponsorship will give it more reach than the £9m-a-year shirt logo deal with Manchester United, ditched last year.

Vodafone is guarded about how what it calls a more "scientific" approach to sponsorship will translate into customer numbers, and it won't reveal any targets. It cites only the market research that one in four consumers views Vodafone's brand more favourably on the back of its Manchester United and Ferrari sponsorship.