Small retailers fight to hold their own against Tesco
Roy Butler is on the front line of the latest retail battle in Northern Ireland.
He owns a Centra supermarket on the Ormeau Road in south Belfast.
Small supermarkets like his, operating under a 'symbol' like Centra or Spar, dominate the convenience shopping market. There are more than 600 of them.
Until last year his main rival was a Mace, just up the road. But then Tesco opened up next door.
"The first two weeks of that opening was like shock and awe. We were in intensive care," he said.
Mr Butler saw turnover drop by more than a third though he has since clawed about half of that back.
He said customers have come back, some making a conscious choice not to be 'Tesco-ised'.
The retail giant is best known for it out-of-town megastores, but it has responded to changing consumer behaviour with a greater focus on smaller shops in residential areas and city centres.
Across the UK there are 1,600 of the small format Tesco Express outlets - just 16 of those are in Northern Ireland.
Two of those branches opened last year - the one next to Mr Butler and another in Larne.
A further three are due to open in the coming months: in Belfast city centre, near Queens University and in the Rosetta area.
Mr Butler accuses Tesco of "targeting" existing shops like his in an effort to "feed-off" their customers.
Tesco said it chooses locations on where they think they will be most popular with local customers.
It claims that existing retailers can benefit because the new shops bring "more footfall to high streets, encouraging people to shop locally".
The growth of these smaller stores are part of broader retailing trends.
People seem to be doing one big shop - often online - every week or fortnight then "topping-up" at the local convenience store.
It might also be that the major supermarket firms have recognised the limits to growth using big stores and have to compete more aggressively in the convenience market.
Last year, Tesco's chief executive Philip Clarke said that while large stores are still a key part of his business "we won't need many more of them because growth in future will be multi-channel - a combination of big stores, local convenience stores and online".
Tesco will not be drawn on how many Express stores it aims to have in Northern Ireland, but for the minute it looks to be steadily targeting residential districts across Belfast.
The existing convenience sector is not without the resources for a fight.
Although the vast majority of stores are independent, stand-alone businesses, they have the support of the 'symbol wholesalers'.
The Centra and Mace brands are controlled by the Cork-based Musgrave group which has an annual turnover of more than 4bn euros (£3.31bn).
The Spar and Vivo symbols are controlled the Henderson group which is locally owned by the Agnew family.
Musgrave and Henderson wholesale to the network of shops and also provide support services like IT and marketing.
But it is going to be the individual retailers who feel the most pressure.
Glyn Roberts, chief executive of the Northern Ireland Independent Retail Trade Association, said those retailers can play to their strengths.
"Some of them have been here for generations, they know the community they serve in the way that the big multiple stores don't," he said.
"Though it will require them to adapt and be nimble to meet the challenge head-on."