The secret ingredient in David Beckham's boots: kangaroo

It puts the spring into Michael Owen's step and the curl into David Beckham's crosses. But animal rights activists are hopping mad: this week they launch a global campaign against footballers who get their kicks from kangaroo skin.

Protesters claim demand for kangaroo leather by boot manufacturers such as Adidas and Umbro has fuelled a marsupial killing spree in Australia. Last year, three million kangaroo skins worth about £12m were exported from Australia, many of them destined for the football pitch.

The quota of kangaroos that can legally be culled has risen in one year by 1.5 million to seven million. A further million "joeys" die – battered to death or left to starve when their mothers are killed, campaigners say. The industry claims that only half the quota is actually "harvested".

The cull has its defenders off the pitch, too: while to British onlookers the kangaroo is the benign friend of Winnie the Pooh and symbol ofAustralia's challenging outback, to many farmers it is a pest that devastates crops and takes food from sheep.

Nevertheless, campaigners plan to picket sports shops from London to Sydney and Paris to New York on Saturday, targeting the leading brands for putting kangaroos in their boots.

"There is no way you can justify butchering millions of kangaroos to turn them into sports shoes," said Claudia Tarry, of Viva!, the animal rights group leading the protest in the UK. "It doesn't matter whether the kangaroo industry, Adidas and the Australian government tell us that every kangaroo dies quickly and painlessly – we know that is absolutely not true. We want to see an end to the commercial kangaroo industry."

Their concerns are shared by the inventor of the best-known boot in the world, the Adidas Predator, as worn by Beckham. Craig Johnston, the former Liverpool midfielder who created the ground-breaking Predator in 1993, originally used synthetic materials. "The original model of the Predator was an all-rubber shoe," said Johnston who cut his ties with Adidas five years ago. "Synthetics, rubbers and new materials are definitely the future of football boots," he said. "I don't agree with killing kangaroos."

The Umbro XAI boot, as worn by Premiership stars such as Michael Owen and Alan Shearer,also gets its bounce from kangaroo skin. Both boots have also proved popular with thousands of soccer fans who, keen to emulate their heroes, will pay up to £130 for a pair of Predators or £90 for a pair of XAIs.

As part of its campaign, which will see 50 separate demonstrations across the UK alone next Saturday, Viva! is encouraging protesters to write directly to England captain Beckham.

"The contrast between the love and adulation David Beckham lavishes on his own offspring and the disregard he shows for the young of a different species is stark," said Ms Tarry.

Beckham's agents declined to comment on the player's footwear.

An Adidas spokesman said: "We insist that our suppliers fully comply with the Australian government's strict rules on kangaroo culling."