As the rain drips over soggy England, I’m putting the final touches to the kit I’m taking out to sunny Zambia – five separate items of luggage so far – and counting.

Heading south I’ll be swapping our summer for the southern hemisphere’s winter. A good time for us to begin our excavations as the temperature is a bit lower this time of year – and the mosquitoes and snakes a  little less hyperactive.

This will be the first season of our new ‘Deep Roots’ project – and it begins in the dramatic setting of Victoria Falls, a World Heritage site in Zambia, Africa.

The rains ended in April, so the Zambezi River should be full and the falls roaring – which is why the local name for them is ‘Mosi oa Tunya’, the smoke that thunders. (Mosi is also the name of a popular Zambian beer, always welcome at the end of a hot day’s digging.)

It’s been a very long journey to reach this point. And it all began with a recce, some years ago.

I’d spent a baking morning poking around for stone tools in the rich red sand of a river terrace, some distance above the immediate falls area. Sweat bees crawled in and out of my eyes and the tools themselves were so sharp they made my fingers bleed.

And I set off back to my 4X4, full of excitement at what I’d found. But.

In Zambia, you’re always dependent on your vehicle – which was off road, miles from the nearest tarmac. In sand.

You guessed. The more I tried to get out the deeper I sank.

I thought I’d been digging somewhere isolated, but no sooner had I become stuck than several people appeared, with shovels, smiles – and muscles.

Shouted instructions, plenty of digging and a few shoves later and we were on our way. And of course I could give them a lift!

Zambians are always ready to help if you break down or get stuck – and rarely expect anything by way of reward – except perhaps a lift. But a gift of biscuits (or football magazines) is never unwelcome, in my experience.

Locals – other than my colleagues in the Museums Board and National Heritage, that is – rarely understand why I am digging, especially when they see the dull-looking results. Not emeralds or amethysts  – which is what people usually think we are hoping to find – but stone tools made up to hundreds of thousand of years ago.

Zambia is a conservative, Christian country and often the suggestion that these date back so far is met with incomprehension, or simple disbelief, as a literal belief in biblical creation has for a long time been widespread. But now human evolution and Stone Age archaeology is being taught in Zambia’s schools – and through this project we are contributing with the latest scientific understanding of the past.

The stone tools, I have to tell our visitors, are not worth a bean, in the financial sense.  They are precious evidence however, of a fundamental change in the way humans thought about tools and made them. And that is what we are investigating over the next five years.

We will be looking for artefacts that span the transition from large hand-held tools – probably used for cutting and chopping – to small flakes of stone that were shaped and used as inserts in tools with handles.

Making – and using – tools with several different parts is something we take for granted because all our technologies today use this concept, but it had an origin.

We want to understand more about when this invention took place and what advantages it offered over long established ways of doing things.

Victoria Falls and the other areas we’ll be investigating over the next four years preserve sequences of artefacts that span the transition from old to new ways of making things.

Zambia is always a great place to work, full of surprises – not always, admittedly, good – but I hope you’ll tag along on our journey. I’m working with a team of both experts and volunteers from Europe and Zambia – and I can’t wait to get started.

Now, where was that trowel?