For many years I have entered the ballot for the London Marathon but not got in.

Then this year it was different, a ballot place but who should I run for?

The obvious would have been a breast cancer charity as I have survived this illness. But I am a GP, and I know so many patients with so many deserving illnesses; dementia, motor neurone disease, other cancers, mental health problems; the possibilities are endless.

I read about fundraising in the acceptance magazine I had been sent and a key comment was "choose a cause for which you have a passion"

Instantly I knew I should run for Guide Dogs.

Over the years I have met different guide dogs in the course of my work, but two years ago I met Emma and her black lab Isaac for the first time. They have been inspirational to me.

Emma has a genetic eye condition that means her vision is gradually disappearing. Seven years ago she got Isaac and has been able to continue in her career as a teacher. When working Isaac is focussed, head down, leading. I know how difficult this is as sometimes I have been out with Emma, and without Isaac in order to give him a rest, and led her using both my arm and verbal instructions. My respect for his work has grown enormously. And yet when we go to the park and let him off the lead he is just like any other dog, cocking his leg at every tree and having fun.

Chatting with Emma I have realised how incredible the costs of a guide dog are. To train a guide dog costs £40,000. A guide dog starts work at the age of eighteen months and works for about eight years before retiring, hence there are considerable ongoing training and replacement costs.

4.11.15

Isaac has retired today, read Emmas blog but be warned, tissues are needed

"Today I signed the papers to retire my beloved Guide Dog Isaac. Weepy and heartbroken as I am, overwhelmingly I feel gratitude. To him – for seven years of being my faithful companion, my buddy, my protector and my eyes. For rebuilding the confidence I had lost and giving me the courage to go to new places and try different things, and enabling me to stay in work and be as independent as possible. For his ability to read me and comfort me – in meetings, at funerals, when walking somewhere I felt vulnerable, Isaac has the ability to reassure me and let me know we were in this together. He also has the ability to break the ice in places I was hugely daunted in and to reach out to people he knew were also vulnerable, from children at school, to those upset or infirm, he would sit at their feet and let them stroke him whilst lying on his back with his paws in the air. He once crawled from under my seat on a train to sit with his chin on an old lady’s knee the whole journey. Towards the end, she told me her dog had past away a few weeks earlier and he had been a huge comfort to her. But mainly, Isaac was my eyes, he enabled me to walk tall again and feel I could go it alone (but with him!), he kept me safe and on the right track. Before I got him, I had fallen down a steep flight of stairs and tripped on pavements, I’d bump into doors and found crowds hard places to negotiate. I had begun dreading being out by myself in public. I am eternally grateful to Isaac for changing all that and giving me my quality of life back.

But I also feel grateful to you – to every person who has ever donated money to Guide Dogs, I would love to say a heartfelt thank you. Your contribution has made lives change, like mine. Those donations enable people like me to keep their independence, grow in confidence and to be welcomed by people in a way my white stick never did. Every day I have walked in public with Isaac, I have been welcomed, loved and encouraged by people, and yes, there is always the minority of people who haven’t welcomed him, but the loveliness of people I meet each day outstrips those few a zillion times over.   And to my friends, colleagues and family who have loved and looked after us, thank you. Isaac has been part of many lives and the way he has been loved has melted my heart.

I have been so blessed. Isaac was a massive answer to my prayers and I will miss him terribly, but I am so reassured that he will continue to be loved and cherished by his new family.

I don’t know how long I will be waiting for a new dog to be found. I had planned to go from Isaac to a new dog, but that wasn’t to be. Today I signed Isaac officially back over to Guide Dogs and handed back his harness, a gut wrenching but necessary. I have friends waiting to be vetted to have him, but until then I get to keep him with me, but retired, so in the meanwhile I will dust of my much less loved white stick and start the process of adjusting to life without my four legged buddy beside me."

So thank you for donating to Guide Dogs to ensure that there is an ongoing supply of healthy, well trained guide dogs so that many, like Emma can continue to live as normal a life as possible.

Donating through JustGiving is simple, fast and totally secure. Your details are safe with JustGiving – they’ll never sell them on or send unwanted emails. Once you donate, they’ll send your money directly to the charity. So it’s the most efficient way to donate – saving time and cutting costs for the charity.