In all the months of writing about running since I started this column in January, I have focussed on health, self-improvement and weight loss.

All excellent goals, but missing one barely mentioned yet incredibly important element of running - charity.

Many run for good causes, often health or medical related, and very often in memory of a loved one.

That is not only helpful to the cause, it is uplifting for those also competing or spectating, and enriches us all.

Charity runners are in all shapes and sizes.

The gazelles of running clubs whip past you with their cancer, mental health or heart T-shirts flapping, while you can also spot the chunky ex-couch potatoes who have got their act together ambling along in the best interests of spinal care, Down's Syndrome or a local hospice.

For the Belfast Marathon I was privileged to raise money for St Margaret's Hospice, Clydebank, and can truly say the commitment required were stick and carrot.

I got great support (and prayers) from Sister Rita and her colleagues, and when injury threatened to keep me from doing the 26 miles, and I was still limping the night before from a foot twist, the need to run the race remained paramount. With £3,000 of direct sponsorship already paid and another £20,000 in a will bequest, there was no way out.

For the 2015 London Marathon, I will run for Jesuit Missions.

Immediately after Belfast in May, I had enjoyed it so much I decided to try for London. It's the biggest and best.

I found I was too late for the public ballot - so after speaking to fellow runners I looked around for a charity place. My interests are social justice, relief of poverty and illness. After application to various charities, only one accepted me - the Jesuit Missions.

So what is my connection? Well, as a Glasgow boy I attended St Aloysius' College, a Jesuit school, and both my children went there.

My father-in-law is the retired headmaster of its primary school, and many friends have connections with the college. So I know a bit about the school, the Jesuits and the Missions.

While a pupil at St Al's, my daughter Hannah spent time in Kenya with classmates helping with education and care of young people there.

The Jesuits say they educate young people to be Men and Women For Others. Charity work is central to that aspiration.

Indeed, when I was at school, along with friends I was involved in fundraising for the missions overseas, and learned of priests, brothers and ordinary people who went overseas to Guyana, Africa, India, and locations where poverty, disease and misery were in large supply.

Whilst the Jesuit Missions is a religious Christian organisation, the work is all practical. Medical treatment, education (often involving building schools out of firewood or bamboo), basic but essential healthcare, were all prioritised and practised in jungles and deserts by men and women who had given up comfort in Britain to live in poverty in the back of beyond.

I was at school in the 1960s and 70s. Right up to date the African Jesuit AIDS Network is helping in the fight against Ebola infection in African countries.

But I won't have to live up the jungle or drive a Land Rover across a hostile terrain to bring medicine to a village rife with disease, I have the easy and indeed fun bit - to run and ask for money.

So nearer the time, I will be opening up a charity giving page and exhorting whoever can contribute to do so.

You won't need to be a Catholic! That is one of the great things about religious people doing charity. There is always great co-operation and overlap among denominations and faiths.

One of the things I am asked and happily do is to contribute to local Jewish charitable purposes in Giffnock through the synagogues.

I am on first name terms with the rabbis.

Being Austin Joseph Aloysius Lafferty is no barrier to being warmly welcomed, though maybe having children with good Hebrew names, Jonathan and Hannah, helps.

We are all Jock Tamson's bairns, and must support each other. I am not political, but believe in fairness, justice and mutual support.

If I need to sweat my guts out and ruin my knees to add a tiny bit to the effort to these causes then that is a small price. If I get a beach body out of it, I will regard myself as a double winner.

The Jesuit motto is Ad Maiora Natus Sum - I was born for greater things. It has been my driver for years and fits this project perfectly.