Southsea man aims to beat his own Guinness World Record at the London Marathon running as his alias 'Terry Rex'

Having donned a 7ft inflatable tyrannosaurus rex costume for a marathon in the Arctic Circle last year, Arnie Delstanche never intended to wear it again.

However, the 29-year-old from Southsea, whose marathon in Tromso, Norway, in June 2025 saw him establish a Guinness World Record, has been unable to part with his dinosaur alias ‘Terry Rex’. On Sunday, April 26 he will be taking on the London Marathon as he raises money for Cancer Research UK as well as a few smiles on the route.

Arnie said: “Not long after I did the Arctic Marathon I got the accepted for a place at the London Marathon for Cancer Research UK. It became one of those things where as soon as I was about to retire this little endeavour I ended up doubling down to train for London.”

Since then he has run in the heat of Southern Spain in August, as well as taking the suit to Canada, Japan, and Switzerland to give it a run out. When he goes on holiday now, he makes sure to bring Terry with him.

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While the idea to wear the suit was for it to be a fun spectacle to make people laugh, it is for a serious cause that is close to Arnie’s heart. He was diagnosed with skin cancer at the age of 20 which was caught early and the treatment worked. He has also lost three family members to cancer.

Arnie said: “If I can raise funds, spark conversations, and make people smile while honouring the people we’ve lost, then that makes every overheated mile worth it.”

He is not the only person looking to beat a Guinness World Record, with all those attempting one being released together. Arnie is aiming to run the marathon under four hours, surpassing his time of four hours, seven minutes, and 46 seconds which saw him take the record of the fastest marathon in a full-body inflatable costume (male).

Arnie said: “I have been in touch with quite a few other Guinness World Record attempters. It such a niche thing to be running in a costume it is quite easy to make good friends when you share a very similar but bizarre hobby.”

While the London Marathon is at the forefront of his mind, it will not mark the end of his journey with Terry Rex. The next challenge lined up is the Sierra Leone marathon in Africa which is taking place in October.

To donate to Arnie’s cause visit https://fundraise.cancerresearchuk.org/page/arnies-giving-page-4

Find the video of Arnie talking to The News in Southsea ahead of his Arctic Circle last year embedded in this article.