About to embark on his sixth day of running, an army captain has raised more than £167k running 27 marathons in 27 days.

Inspired by Eddie Izzard’s Sport Relief challenge, Captain Scott Fisher has taken on the mammoth mission to raise money for Mast Cell Action, a charity which supports his wife.

Scott's wife Megan was struck down with Mast Cell Activation Syndrome (MCAS) in 2018 following the birth of her child.

Triggered by severe sepsis, the ex-Army Reserve and national level equestrian competitor suffered from one unexplained symptom after another.

She was affected by all manners of skin and digestive problems, seizures and anaphylactic shock.

The illness then also turned into an inability to take in any food and calories and led to her loosing more than 20kg and needing mobility aids.

In the following three years, nobody was able to satisfactorily diagnose her illness, despite multiple spells in hospital.

Megan and Scott then took it upon themselves to research her symptoms and were finally able to get the illness diagnosed as MCAS after a referral to two specialist hospitals in London.

To manage her condition, Megan, who is now incapacitated and bedbound, takes 27 pills a day, counted out by Scott.

The Royal Engineer from Chatham appeared on This Morning on Wednesday with donations pouring in afterwards. He said: "I started researching challenges and the first one I stumbled across was Eddie Izzard’s 27 marathons for Sport Relief.

"The parallels with Megan’s 27 pills a day leaped out to me. I thought it could be a great way to help draw attention to the little-known disease."

MCAS forms part of a spectrum of mast cell disorders and - due to its complex nature, a lack of universally accepted diagnostic criteria and access to tests under the NHS - it becomes challenging to diagnose.

It is a rare syndrome that only affects 17% of the general population.

Mast cells provide an important line of defence in our immune systems and in people affected by MCAS their cells respond too frequently or excessively to things that are not typically considered harmful.

This can include foods, chemicals, drugs, fragrances, temperature, exercise, stress, hormonal fluctuations and infection.

Today is Scott's sixth day of running after starting his challenge earlier this week and he will be running consecutively until January 6 – even on Christmas Day.

In the hope to raise £27,000 for Mast Cell Action, he has now topped more than £167,000 at the time of writing and after appearing on This Morning, viewers had raised more than £100k.

The charity is determined to raise awareness, provide support to patients, their families and doctors and fund research into the syndrome.

If you would like to donate to Scott's fundraiser you can do so here and you can also follow his journey on Instagram @marathons_4_mast_cell.