By Ed Conway, economics editor

The Charlotte. The Electra. The Lady Claire. The Pentland, the Taurus, the Jester, the Desiree.

Nobody knows for sure how many varieties of potatoes there are in the United Kingdom. The Agriculture and Horticulture Development Board (AHDB), the official arbiter of these things, puts the number at 334 but others say it's 500 and at least one potato farmer I've spoken to reckons the real tally is well over a thousand.

It is, in short, a lot, and if nothing else this underlines one thing. The potato might not be a native UK crop, having been imported to Europe from the Americas by the Spanish in the 16th century, but few countries have made the spud a part of national culture in quite the way Britain has.

Kettle Chips, who make crisps in Britain, say they may have to consider moving some of their production abroad, in the event of a no-deal Brexit.

Fish and chips, mashed potatoes, roast potatoes and, most of all, crisps.


The origin story of the potato crisp is lost in the mists of time. The most commonly-cited version says they were invented in 1853 by a George Crum, a Native American chef at the Moon's Lake House Hotel in Saratoga Springs, New York, when a diner kept sending back his French fries to the kitchen complaining they were not thin enough.

Crum cut wafer-thin slices, fried them in oil and covered them in salt. The customer, it is said, loved them so much they soon became an institution.

Image: Crisps are cut to between 1 and 2mm in width

Yet there are also reports of British recipes for something akin to crisps dating back long before that; others claim that the idea originated from France.

Whether or not Britain invented the crisp, it has made them a national institution in a way few other countries have.

In a country which defines itself based on class, eating crisps is an oddly universal pastime.

Consider, as evidence, the Prime Minister's celebratory snack after she won her recent no confidence vote for the Conservative leadership: "Two glasses of red wine and some crisps."

It is not clear which flavour she favoured, though if she were reflecting the national mood she'd have chosen cheese and onion, the country's favourite variety.

Image: Tim Papworth explains what is the perfect size for a 'crisping' potato

How did the UK become one of the world's leading crisp producers? The short answer is the same as why Britain is the world's leading sandwich producer. This is a nation of snackers.

Other countries - the French, for instance - tend not to have a national habit of eating on the go. But Britons' appetite for salty, portable snacks has long been prodigious.

Britons consume billions of packs of crisps each year - and while the numbers are starting to flag due in part to health concerns, evidence suggests that rather than dispensing with snacks altogether, consumers are simply switching to alternatives such as popcorn or vegetable fries.

This helps explain why the UK is home to some of the world's most renowned crisp manufacturers, from Walker's in Leicester to Tayto in Northern Ireland. Why it pioneered the development of high quality crisps in a way most other countries can only envy.

Indeed, as well as satisfying an enormous national habit, Britain's crisp industry is also one of those rare things: a British sector which exports all around the world.

Kettle Chips exports about 15% of the crisps it manufactures in its Norfolk factory to Europe and further afield.

And while most of the major crisp brands, from Walkers to Tyrells to Kettle, are now owned by international groups, the striking thing about the crisp industry is how, well, British it is.

In this era of global supply chains, where the camshaft of a car is made in one country, the windscreen wipers are made elsewhere and the whole thing is assembled in another country entirely, nearly every stage of crisp production is domestic.

Image: From raw potato to bagged crisp in just 45 minutes

Some 96% of all potato crisps in the UK are made from homegrown potatoes. Kettle Chips prides themselves on making their crisps from potatoes grown within a few miles of the factory itself.

Which brings us to the key question: how do you make a good crisp?

And it turns out there is much more science in it than you'd think. Different crisp manufacturers jealously guard details about the temperature they fry their crisps at and for how long, about how they mix the flavours and sift the crisps. But there are some broad lessons.

So, for instance, your common-or-garden crisps tend to be cut quite thin, around 1mm. But these days "quality" crisp manufacturers tend to cut them thicker - around 1.5mm or 2mm slices - resulting in a crunchier bite.

Much depends on the potato varieties used. The Maris Piper, Britain's number one favourite, is great for mashing or cutting into chips, but is too big to slice into a satisfying crisp.

The ideal crisping potato is small, but not too small ("It is not", says one farmer with a sniff of disdain, "one of those awful salad potatoes"). Big enough to fill your mouth without sharp edges. Something like a Lady Rosetta, a Markies or a Daisy.

Then there's the water content. Broadly speaking 80% of the weight of a potato is water - but the percentage varies.

Some varieties have too much water and too little of what crisp makers call "dry matter" - the upshot being they shrink the minute they go in the fryer. The ideal crisping potato has about 20% to 25% dry matter.

But too little water and a potato can simply die. And that was precisely what happened throughout much of the country in 2018.

The Beast from the East in the spring and the blisteringly hot summer wreaked havoc for potato farmers, who rely on the weather remaining relatively stable. As a result, across the country this was the worst potato harvest in more than half a decade - the fourth worst on modern record.

"For some farmers it was an absolute disaster," says Tim Papworth, a potato farmer in Norfolk.

He was one of the lucky ones: his yields fell but not as precipitously as other farmers in the Midlands, where temperatures clung above 30 degrees for an extended period. "It was such a hot summer, some potatoes just died off in the ground."

If you buy enough crisps you may notice the effects in the next year or so. Prices of potatoes have risen, and in response to the diminished crop crisp manufacturers have tweaked their plans.

Kettle Foods, which buys potatoes from Tim's farm, previously stipulated a minimum diameter of 40mm. Now that has been reduced to 35mm.

If you wonder why the crisps in your packet are a little smaller than they once were - here is your explanation.

The potato harvest is the main challenge facing the industry this year but here as in so many other areas of UK industry, there is an overarching concern: Brexit.

The concerns apply all the way up the food chain. Farmers like Tim are nervous about what Brexit will spell for the agriculture industry.

Although potatoes aren't covered by the Common Agricultural Industry's payments, the entire sector is reliant on government support and, crucially, government regulations.

And while Britain produces most of the potatoes it needs, farmers still have to import things like agricultural chemicals (fertiliser, pesticides and so on) from Europe.

According to Tim, some farmers have started stockpiling these chemicals ahead of Brexit day, in case they go up in price or become more difficult to obtain.

Labour is already coming under pressure: the farming industry is reliant on short-term migrant workers during harvest season. This year the numbers dropped sharply and it proved hard to find workers.

For Kettle Foods managing director Ashley Hicks there is another threat. At the moment Kettle pays no tariffs on any of its exports to Europe - exports which account for 15% of its total production of crisps.

Should there be a no deal Brexit and the UK faces having to pay EU tariffs, that means paying 10% on every pack of crisps.

Kettle has always made all its potato crisps in the UK from British potatoes, but Hicks says if the company faced those tariffs - not to mention the threat of disruption at customs - he is prepared to shift production to the Netherlands.

For the first time, the company's crisps - at least the ones sold in Europe - would not be "made in Britain".

Image: Kettle Foods managing director Ashley Hicks says some production may move abroad if there is a hard Brexit

There are other concerns too. What happens to British food standards and regulations if we leave the EU? At the moment Britain has more stringent rules on food and agriculture than many other countries.

In the UK potato farmers are banned from pumping chemicals into their potato storage sheds, but there is no such ban for American farmers.

If Britain seeks a US trade deal does that mean allowing gas-flushed potatoes into the country? Does it mean changing the rules here?

Still. Brexit is hardly the only long-term concern in the industry. After all, for all the popularity of the potato chip, it is hardly a darling of the public health community, which is waging war on oily, salty products.

Indeed, the growth products in the industry these days are newfangled snacks like popcorn, quinoa chips, hummus chips, sweet potato fries and so on.

These may be marginally more healthy than their potato-based siblings, but there is an important difference. Unlike potatoes, the crops behind these snacks are generally not grown in the UK.

In other words, as we start to choose healthier snacks, we are at risk of putting British farmers out of work.

Back at the Kettle Chips factory, those remain distant concerns.

In the meantime it is hard not to be impressed as one watches this - one of Britain's strongest sources of comparative advantage, in action.

The production line can process 250 tonnes of potatoes in 24 hours. It takes a mere 45 minutes for a potato to come through the production line, be washed and sifted, sliced and fried, salted and seasoned, bagged and boxed.

Within two hours the potato picked from Tim Papworth's field has become a pack of crisps on its way to the supermarket shelf.

Britain's favourite crisp flavours:

1. Cheese & Onion

2. Salted

3. Salt & Vinegar

4. Chilli

5. Prawn Cocktail

Source: SNACMA