Boris Johnson picked the home of Tayto crisps in the North this week as his photo stunt while on the hustings, hawking his Brexit deal ahead of next month’s crunch British general election.

From the factory at Tandragee Castle in Co Armagh, the British prime minister declared himself a great fan of Tayto, mentioning how he recently munched his way through a big “sack of them” in Downing Street.

Johnson also denied there would be trade checks between the North and Britain under the terms of his tweaked Withdrawal Agreement - much to the confusion of anyone who heard his Brexit secretary testify in the House of Lords that businesses will have to fill out “exit summary declarations”.

“The idea that Tayto crisps from Tandragee are going to be vetted by some process is just nonsense,” Johnson said.

As with everything in the Brexitshambles, it threw up more questions than answers. Will Northern traders face extra paperwork when shipping to Britain? Is that tantamount - as some unionists fear - to a border down the Irish Sea? And, what is the difference anyway between Tayto in the North and Tayto in the South?

Indeed, what is the difference exactly?

Tayto as the gods intended them to be.

In fairness, the last question pre-existed the UK’s decision to leave the EU, but it remains an old chestnut. And one which, in these dangerously divisive times, poses the schism-inducing question of which tastes better?

As with all things Irish, first a bit of history.

Southern Taytos - referred to by Notherners as Free Staytos - are the original (and, according to rock n roll star, Liam Gallagher the best).

Known for their red, white and blue packaging - just to add to the confusion - they were born of an idea by Dubliner Joseph “Spud” Murphy.

A serial entrepreneur, who had already started importing the likes of Ribena blackcurrant cordial and ballpoint pens into Ireland, Murphy hit upon making crisps in Ireland at a time when they were mostly bought in from the UK.

In 1954, he opened the Tayto company in O’Rahilly’s Parade, near Moore Street, in the capital.

Together with one of his eight employees, Séamus Burke, he is credited with inventing the now ubiquitous cheese and onion while working at a kitchen table, experimenting with ideas for flavours. Born out of the brand are Mr Tayto, the cartoon-like character on every packet, and an entire theme park in Co Meath, called Tayto Park.

The Ashbourne park is right beside the factory where the crisps are made. These days Largo Foods aka Tayto Snacks owns the Tayto brand, as well as Hunky Dorys, King crisps, Hula Hoops, and the Perri and KP snack brands.

Jeff Swan, Managing Director of Tayto Snacks, pictured at the factory near Ashbourne, Co Meath. File photograph: Dara Mac Dónaill

Tayto Snacks, which is now wholly owned by German group Intersnack, operates from an 80,000sq ft facility close to Tayto Park, which is separately owned by the snack manufacturer’s former shareholder, Ray Coyle.

The crisp brand has come a long way. The crisps were first sold out of a single delivery van before a deal involving the Findlater family’s stores and distribution network unleashed them throughout Ireland. Now they are shipped all over the world to ease pain of being away from home for those who live outside Ireland.

Tandragee Tayto

Meanwhile, up North, another businessman - Thomas Hutchinson - was wondering what to do with a 500-year-old Tandragee Castle in Co Armagh he had just acquired in 1955.

The absolute stayto of it - Northern Ireland Tayto comes in a yellow packet.

He, too, hit upon the popularity of crisps as snacks and approached his crisp-making counterpart in Dublin to do a deal for the rights to the name Tayto and its recipes for outside the Republic.

The following year he set up a Tayto factory at Tandragee. They are known today for their distinctive yellow coloured packet.

Personal tastes differ and arguments rage over which are the tastier of the two - northern Taytos or southern Taytos?

While Oasis rocker Gallagher is firmly in the red, white and blue corner, the likes of Liam Neeson, Rory McIlroy and Snow Patrol are said to be devotees of the yellow packets. And, of course, Boris Johnson, if you could believe him.

And much like the rest of Irish history, the tale of the two Tayto companies throws up questions of shared and separate identities.

So much so, that a trademark row involving both ended up in the High Court in Belfast in recent weeks.

Sole trader Mark Ferris accepted in court that he had breached Northern Tayto’s rights to the name by selling southern made Taytos to shops and pubs in Northern Ireland.

The businessman from Ballynahinch, Co Down, could be liable for damages over the infringement.

Speaking to a local newspaper recently, he said his phone hasn’t stopped with people offering him messages of support including from clergy in the Catholic Church.

One of his Co Tyrone customers told him they “would never buy the Northern Ireland Tayto crisps again”. Mr Ferris now only sells northern Tayto.