What if someone told you a Peugeot 407 (2007 model) might set you back €16,000 in Dublin, but if you hop on a bus up to the North the same car is £8,000...

There must be a catch? Well, there’s not.

There are hundreds of comparisons like it for big brand items — £876 for an IKEA kitchen here, a flat €3,000 down South; Currys 32ins HD TV;— £200 here, €549 in the ‘Rip-off Republic’.

“I meet Irish consumers from Belfast Central Station more often now to take them to our showrooms on the Boucher Road,” said Ian McAllister, general manager of Charles Hurst Motors.

“Southern car buyers can get great deals now, especially on second-hand cars. They can save between €4,000 and €6,000, even taking into account the differences in VAT and other charges.”

The price differences also apply to ‘small' items — even the humble bag of spuds.

In Tesco, a bag of same-brand potatoes is 99p here but €5.99 over the border; Barry's tea is £2 at a store near you, €5 at a store (thankfully) not near you; Wolf Blass yellow label chardonnay (75cl) £5.99 on shelves in Sainsbury's here, €12.05 in Superquinn down there.

Even taking into account currency rates, tax differences, wages, rent and other costs, it remain head-scratchingly bizarre.

“As a small country importing most products from the UK, I believe there will always be a price difference between Ireland and the UK,” said Jamie Lawrence of dualpricing.ie, a website dedicated to exposing price hikes.

“However, I'm equally convinced that many retailers are exploiting the consumer's ignorance of the real currency and VAT differences.”

As a Southerner now living in Belfast since 2006, I notice the difference more and more. On regular trips down to Dublin, I see hordes of shoppers jumping on the train at Newry weighed down with shopping bags.

While this used to happen, it was really just for designer clothes, but now it's for items as humble as basic groceries.

“I come up for the chickens,” a woman on the train told me two weeks ago. “I get free travel with my pensioner's pass so it's worth my while.”

She saved more than €3 per whole chicken and was able to get the frozen macaroni cheese her grandson loves for “half price” at Sainsbury's in Newry.

There were also some shoppers on the train who’d stumbled across an off-licence and couldn't believe their luck.

“The price difference with booze is unbelievable in both places,” said Elizabeth Reapy from Galway, who is at Queen’s.

“A 750ml bottle of Smirnoff vodka in my local off-licence in Botanic in Belfast is £11.50. In Galway the same bottle is €23!

“Taking into account the currency difference, it should only be €12.74, so where does that extra €10.74 come from?”

At the moment the currency rate is £1 = €1.10842, but it could get tighter still, with some experts predicting that both currencies will reach parity by next year.

The euro, which as recently as July 2007 was trading below 67p, touched a record high of 98.03p last month.

“I bought a Canon 1000D camera for my partner for Christmas for £390 in Jessops of Buttercrane, but, bizarrely, the same model was on sale in Dublin for €540,” said Dublin-based writer Suzy Byrne. “And I don’t feel unpatriotic!”

Two months ago Irish Finance Minister Brian Lenihan sparked controversy after suggesting consumers from the Republic who buy goods in the North were “unpatriotic”.

It was a ‘red rag to a bull’ scenario and since then the unpatriotic desperate to save a few bob have been belting up the motorway to shop here.

Conor Pope of pricewatch.ie says Southerners became more aware of the bargains ‘up North' before Christmas when some stores began offering one-for-one with euro and sterling prices.

“Even the most arithmetically challenged consumer was able to work out instantly that the numbers on the price tags did not tally with the realities on the foreign exchange markets,” he said.

The biggest retailer in both jurisdictions is Tesco. According to Conor, its currency conversion “seems to be at odds with reality”.

“It is selling shirts in the Republic with a euro price of €30 and a sterling price of £20, while Gillette razors, which cost

£2.92 (€3.12) in the UK, cost a fairly hefty €6.36 in Tesco in Dublin,” he said.

“I used to shop at Tesco until recently when I noticed their prices were still going up despite vows saying otherwise,” admitted Michael Tonra, a worker and trade unionist at Guinness in Dublin.

“I got so fed-up that I wrote a big long letter to Tesco outlining all the cost discrepancies between their UK prices and Irish ones.

“It took months to get a reply, but when I did it was so matter-of-fact that it didn't explain these price differences sufficiently.

“I have now taken my shopping to Aldi, but at least twice a month I will drive up to the North to stock up on food.”

The reply letter Michael received said: “Sorry that you're unhappy with the price we charge for our items in the Dublin area. But perhaps it's misleading if you just look at the price of a few items...

“At Tesco we try to be as competitive as we can with our prices, but we never promised that we would undercut all the prices charged by other retailers.

“Despite the fact that, on occasions, individual products may cost slightly more, our prices are generally considered to be amongst the lowest in the country.”

Now that recession is here, our Southern compatriots are casting a beady eye on the shops up here more and more. They are also asking: “Why did we put up with this for so long?” So, with the huge rise in consumer awareness during the recession, are retailers starting to take note of the situation and do something positive to rectify the price differences?

In short . . . no. Next, H&M, Debenhams, Argos and Top Shop have been accused of failing to pass on exchange rate savings to shoppers in the Republic, while online retailer play.com was found to be selling some game consoles to customers in the Republic for over 100pc more than British shoppers, according to pricewatch.ie.

“I have noticed that a lot of shops around Dublin have started to conceal the sterling prices,” said city-based Zambain Mutale Kampuni.

“Retailers are trying out the ‘ostrich principle’ on us, but it's just not going to work.”

Mutale and husband Ken McCue plan on moving to Belfast soon.

“It is simply a matter of necessity,” said Ken.

“It is a hand-to-mouth existence down there and even a quick browse on the ‘property to rent' websites makes comparing the two places makes me want to scream.

“The exact kind of houses that rent for £600 in Belfast often cost around €2,000-per-month in Dublin.”

A report by the Department of Enterprise after a survey by the National Consumer Agency in June 2008 found that selected branded grocery goods were up to 30pc more expensive in the South than the North last year.

Yet, the difference should only add around 6pc to the prices and not the additional 30-50pc consumers are seemingly asked to pay.