This may not be the finest article ever published by the Guardian, or the best that I have written. After 17 days on hunger strike outside the Foreign Office, I have to admit I am slowing down both in my speech and in my thinking. Until the weekend, I was on a long plateau, but each day now feels like a descent. I am very tired. It’s probably the body saying, “be careful: do not take this too far”. It is not that I am hungry, although I have a strange desire for scrambled egg on toast, a food I do not especially like. The black coffee that I drank last week is now impossible. It makes me too sick. A couple of veterans have told me to take water with salt. People ask whether this self-inflicted punishment is worthwhile. But I felt I had no choice: it seemed the moral thing to do. I felt that if I did not act, it was likely that within weeks my wife, Nazanin Zaghari-Ratcliffe, who has been furloughed from jail in Tehran, would be sent back for a second sentence. By acting, I hoped to forestall this. There is a blockage at the heart of this, which has been recognised by former Conservative foreign secretaries. The UK has an acknowledged £400m debt to Iran, and if it is not paid neither Nazanin nor the other British hostages will come home. For more than a year it has been said that the prime minister, foreign secretary and defence secretary want to pay this debt. Yet it does not happen, and no explanation is ever given. I’m concerned that they plan to link the British hostages to those in the US in order to secure a block deal, bringing British and American prisoners home together and making the debt a constituent part of this jigsaw. But this would be an act of folly, for both British and American political prisoners. I don’t think the US is forcing the UK to do this; rather, it seems the UK wishes to stand alongside America. This is a reckless, irresponsible policy choice. It would be even worse, of course, if the release of the prisoners was linked to material progress on the Iran nuclear deal. There would be so many dynamics and concerns at play, including domestic politics in Iran and US. This debt is a bilateral issue between the UK and Iran. There is a moral hazard here: it is a debt that has to be paid, a legal obligation. It is not a ransom demand: the longer this debt is left unpaid, the greater the anger and the more interest Iran will demand. The UK has allowed hostages to be taken because of it, and if it is not paid soon I suspect other hostages will be taken. Our family has become part of an acceptable level of collateral damage. Nazanin is of course worried about where this will go. She has herself been on hunger strike in prison and knows what effect it can have on the body. My first hunger strike in summer 2019 outside the Iranian embassy was undertaken alongside hers; I ended mine after she ended hers in 15 days. She was in control, but feels less so now. She sees the pictures of me on social media and elsewhere. She watches the weather on the internet to see how cold it is in London, and asks me to be careful. A danger with hunger strikes is that you become more stubborn and less flexible, and it’s important this is not taken too far. I would never let my daughter, Gabriella, go from two parents to none. I have no death wish. At the same time it is important that she sees her dad battling for her mum. She understands more of what is happening now than she did two years ago. She knows that Daddy is on hunger strike to get Boris Johnson to bring Mummy home. When this is over, she will know she went to Downing Street to deliver the petition. Amid all this angry politics, I have been struck by the care and kindness of strangers – packages sent via Amazon, the visits from old friends, former teachers from school or university, my old boss. It is not food, but it is sustenance. Our story is dark in many ways, but that reminder of kindness is absolutely central to survival. Richard Ratcliffe is the husband of Nazanin Zaghari-Ratcliffe. He works as an accountant and lives in London. His campaign to free his wife can be contacted via @freenazanin