Tens of thousands of seaweed capsules filled with energy drink will be handed out to competitors at the London Marathon as part of efforts to reduce the vast amount of plastic used at the event.

Around 650,000 plastic bottles were provided at last year’s marathon and, while they were recyclable, their use was branded a “waste of resources”.

Organisers are trialling a range of innovations and measures aimed at cutting plastic use and reducing waste at this year’s marathon.

The event will see the largest ever trial of Ooho seaweed edible and biodegradable capsules, more than 30,000 of which will be handed out at the 23rd mile.

The capsules are made from brown seaweed, which inventors say is one of nature’s most renewable resources.

Elsewhere on the route, three Lucozade Sport stations will use compostable cups rather than bottles.

Organisers said they aim to cut the number of plastic bottles on the course by more than 215,000 at this year’s event.

Following the 2018 marathon, Tory MP Pauline Latham criticised the sight of discarded bottles “dozens deep along the streets”.

“We need to keep people like that hydrated, but actually using single use plastics is such a waste of resources and there should be better ways,” she told the Commons.

As well as efforts to cut the number of bottles in use, organisers are testing ways of recycling them more effectively.

Using a “closed loop” system, plastic bottles collected in Tower Hamlets, Greenwich, Southwark and Canary Wharf will be returned directly to a reprocessing plant where they will be recycled into new bottles.