Winners at this summer’s London World Championships have been assured they will be able to pass on their medals to their grandchildren after news that more than 100 won at the Rio 2016 Olympics and Paralympics had begun to disintegrate.

The affected Brazilian medals, which were mainly silver and bronze, have started to rust or develop black spots after they were made with 30 per cent recycled materials as part of a sustainability drive.

The Brazilian Mint has ebeen entrusted with returning the medals in question to their former glory, but London 2017 organisers are adamant the problem will not arise this summer.

Unveiling the prizes on offer on Sunday, organisers confirmed the medals are wholly made from new materials and consist predominantly of brass.

The medals for both the World Championships and World Para Athletics Championships – which are taking place together in the same city for the first time – have been designed around the question of “what makes an athlete tick” and contain symbols of every event.

Asha Phillip - London 2017 World Championships vows medals are made to last – not to rust like Rio 2016 prizes did
Asha Phillip, the British sprinter, will be hoping to get her hands on her own medal this summer CREDIT: GETTY IMAGES

Pole vaults, batons and starting blocks are just some of the items to adorn the World Championships medals alongside an image of a London skyline featuring the likes of Big Ben and Tower Bridge.

The World Para Athletics Championships equivalent also contains a wheelchair, prosthetic running leg and blind fold.

A number of leading British athletics figures were involved in the design process, including Commonwealth long jump silver medallist Jazmin Sawyers and Jessica Ennis-Hill’s former coach Toni Minichiello.

“You don’t need too much motivation going into a home World Championships, but being part of the panel and having helped to choose such great medal designs really does make you want to win one,” said five-time Paralympic medallist and triple world champion Dan Greaves, who was also involved.

“The medals are unique and I really like how my event, the discus, is represented along with all the other disciplines.”