Jamie Livingstone, head of Oxfam Scotland, explains how he coped living on £1 a day for a week, and how it compared to a life of poverty at home or abroad

Looking back it was said with embarrassing dismay: "What do you mean we can't afford coffee?"

The reality of surviving on £1 a day for all food and drink sunk in fast at 6am last Monday morning.

I was joining thousands of people across the world in the Live Below the Line campaign, agreeing to spend just £1 a day for five days on all my food and drink.

All of us who willingly signed up for the challenge were joined by the 1.2 billion people across the world that live below the extreme poverty threshold of just £1 per day, every day.

As well as food, their £1 has to cover accommodation, clothes, medicine, education – everything.

My five day participation has provided barely even a snapshot of their reality and even then, I found the experience tough.

As the week wore on the awareness raising purpose of the challenge really came through with conversations over who got what, and when.

I knew when a spreadsheet was involved that it wasn't going to be straightforward.

After touring three low-cost supermarkets for the best deals – something simply not possible for many people – my wife and I had spent our combined £10 allocation.

With so little to spend a day, the 3p saved on bread or 2p on potatoes really counted.

Our stock included lentils, pasta, bread and noodles, all sourced at the lowest price we could find. A 55p pepper was unaffordable, three bananas would need to suffice – this was quantity over quality.

Water was the only drink available. No coffee and certainly no alcohol.

Our shared luxury item was a 30p value bar of chocolate – two squares each a day. Yet there was still genuine concern that we simply wouldn't have enough food.

As the week wore on the awareness-raising purpose of the challenge really came through with conversations over who got what and when.

When my wife gave up her share of a tin of beans to make sure I had enough, it brought to mind news headlines of parents going without food to ensure their children can eat.

Such shocking realities put the challenge of eating on a budget in stark focus.

The truth is that many of the difficulties I faced were minuscule in comparison to the fact that one in eight people around the world simply don't have enough to eat.

Having to plan out meals and portion sizes or attend working lunches only to drink water was awkward but by no means life-threatening.

I have seen the harsher realities of extreme poverty during my time with Oxfam Scotland, including small-holder farmers in Tanzania battling the changing climate to eke out enough to survive.

Underpinning this scandalous reality is deep-rooted and extreme levels of inequality both between and, crucially, within countries.

As it stands, just 85 people share half of the world's wealth and seven out of 10 people live in a country where economic inequality has grown over the past 30 years.

It isn't something that has passed the UK by either: here the poverty may be relative but the inequality remains shocking with just five families owning the same wealth as the poorest 20% – that's more than 12 million people.

And for those at the bottom of our economic ladder access to enough food is an increasing problem: 71,000 food parcels were given out in Scotland last year by the Trussell Trust alone.

Other providers, like our partners the West Dunbartonshire Community Foodshare, echoed the exponential surges in demand recorded by the trust's outlets.

And it's not just those out of work who need support either. Increasing numbers of people with jobs simply don't have enough money to feed themselves and their families.

Across the world, Oxfam believes inequality of wealth, income, and power underpins and exacerbates such poverty. As such, we believe inequality has reached levels which demand action.

I am under no illusion that my five days below the line remotely compares to the daily fight for survival of so many people around the world.

I have now returned to my usual diet – for too many people there is no such choice.

As such, we owe it to them and ourselves to continue to fight against extreme inequality.

Jamie Livingstone is head of Oxfam Scotland. Tweet @oxfamscotland and @JamiePolitics.