A pharmacist hopes to be head and shoulders above the rest of the runners at the London Marathon as he aims to beat a Guinness World Record wearing an eight-foot-tall oak tree costume.
Rob Duncombe, chief pharmacist at The Royal Marsden NHS Foundation Trust, is to take part in the event on 2 October to raise funds for The Royal Marsden Cancer Charity.
The bulk of funding is to go towards the charity's Oak Cancer Centre appeal, which aims to support the development of a "state-of-the-art" treatment and research facility at the hospital's site in Sutton.
The facility is set to open next year and will include more than 400 researchers, 350 clinical staff and thousands of patients together under one roof.
In a bid to do something "slightly different" to raise money, Mr Duncombe said he thought: "Well, because we're building a unit called The Oak Cancer Centre, wouldn't it be quite fun to do the London Marathon in a tree costume?"
The idea blossomed from there when Mr Duncombe discovered that there was already an existing Guinness World Record for the fastest marathon dressed in a tree costume (male), which stands at four hours, five minutes and six seconds.
The outfit has been custom-made by the costume shop Rainbow Productions.
The 54-year-old from Chelmsford, Essex, told PA: "It is absolutely stunning - you can definitely tell that it is an oak tree - and mine was one of the biggest they've ever made, given the height and leaves on top."
He added that the costume took around a month to six weeks to complete and is "relatively light," weighing around five or six kilos.
Despite this, training in the outfit has not been easy.
"It's uncomfortable, it's heavy, it bounces up and down on your shoulders, but it's definitely doable," he said.
"I can keep up a reasonable pace in it and one of the most entertaining parts of training has been doing local park runs down in Chelmsford.
"I think some people get quite upset when they are overtaken by a tree."
He said he hopes to clock a time of four hours on the day and run alongside other people in "silly costumes" as part of an event which has "the best atmosphere".
When Mr Duncombe took part in the London Marathon in 2017 he met a member of the Royal Family along his journey.
"2017 was the year where the focus was on mental health and Prince William, Prince Harry and Kate were heavily involved," he said.
"I was suffering that year - I was cursing and swearing about how awful the whole thing was.
"I went to go get a drink and Prince William handed me one and he probably caught a torrent of abuse from me as I took the drink from him.
"But they all wished me on the way and it gave me a boost over the last mile - it was such a highlight."
He added that being part of The Royal Marsden is "absolutely amazing".
"We are constantly developing new treatments for cancer and not many people get that opportunity throughout their careers to see drugs from the very early stages of development through to extending the lives of thousands of people across the world," he said.
"Cancer is going to affect sort of one in two of us at some point in our lives and The Oak Cancer Centre is a way of creating a really good environment for our patients to receive treatment in and also for us to continue to do research as well."
So far, just over £200 has been raised out of the £3,000 target.