Laura Janner-Klausner is often so tired that she falls asleep at work and carries a pillow, ear plugs and eye mask wherever she goes.

Reform Judaism’s senior rabbi is not lazy — she has revealed she is one of 250,000 people in the UK who suffers from chronic fatigue syndrome (CFS).

She spoke publicly this week for the first time about her life with the debilitating illness which causes fever, aching, prolonged tiredness and depression in the hope it will break the stigma attached to the condition.

CFS, also known as ME (myalgic encephalomyelitis), is a long-term illness and has no cure.

Rabbi Janner-Klausner said she had suffered with it for more than 20 years but had been determined to work twice as hard.

She says: “As I’m talking to you now I’m lying down on my floor. People that don’t understand the condition assume that people with it are lazy or unreliable.

“It is frustrating because CFS means I’m more susceptible to infection than your average person and my body feels totally exhausted and in pain regularly.”

She first discovered she had the condition after contracting glandular fever.

“My problem was not taking it seriously enough. I kept slipping back into it and in the end it turned into chronic fatigue.” Rabbi Janner-Klausner would spend weeks at a time fighting infections such as flu or the common cold.

By speaking out about her experience she hopes to raise awareness of the condition which is more common in women and tends to develop between the mid-20s and mid-40s.

“It means your immune system is completely depleted. It is impossible to explain but you feel it in your arms, your hands, even in your gums.

“I would pick up whatever illness there was and spend weeks at a time wiped out by colds or flu. It is frustrating because you just want to be well.”

The stress brought on by the child abuse accusations made against her late father Lord Janner had “exacerbated” her condition, she says.

“The past four years have been particularly hard.”

Last week she took part in the physically draining March of the Living. She says: “I was very careful to get a lot of sleep and have enough time also to exercise the emotions out of my body.

“I ate a lot and slept at every opportunity on the coach.”

A combination of therapy and exercise has helped the rabbi manage the condition. “I have therapy once a week, which is kindly paid for by a congregant, and I regularly exercise. I go to boot camp with my friend Judge Rinder and his support has spurred me on.”

She also has to have regular injections of vitamin B12 to strengthen her immune system and has to have a minimum of eight hours sleep a night.

“Having supportive colleagues really helps, and my husband David has been my rock.

“They know I work hard and they trust me. I just want people to know that the condition, even though you don’t get rid of it, is manageable and there are ways you can cope.”

Rabbi Janner-Klausner appeared on the BBC World Service’s Heart and Soul with Caroline Wyatt on Sunday. Ms Wyatt, who suffers from MS, is a friend and convinced her to speak out.