Symbol operator Select & Save has grown by almost 50% in the past year - and says it has done so by standing up to Tesco.
Since opening its 100th store last January it has opened a futher 45 stores.
Retail development manager Tony Houlston said the growth was mainly down to an ongoing campaign, first launched last year, in which Select & Save claims to be cheaper than Tesco on a series of key convenience lines.
The drive uses outdoor poster sites near stores and targeted leafleting.
"Independents can see we are the only symbol group actively taking the fight to Tesco," said Houlston. "It has been a real success for us in terms of recruitment."
Its most recent campaign, which ran from 12 February until 4 March, included deals such as two 2-litre bottles of Coca-Cola for £2 and an 18-pack of Carlsberg 440ml cans for £8.99. It claimed in its promotional leaflets that the Carlsberg deal represented a saving of £4 on Tesco, and Select & Save was "always better on beers".
Houlston also said that enticement offered to Costcutter retailers last autumn had stirred up significant interest and the group was still processing applications from retailers. During merger talks last year between Costcutter and Nisa-Today's, Select & Save offered Costcutter members a deal worth £50,000 to switch fascias.
Select & Save is also working with off-licence chain Bargain Booze on developing a joint-fascia concept, Bargain Booze at Select & Save. The project is being trialled at Manton, near Worksop.
Both groups said the tie-up would give them access to outlets that may not otherwise be considered for membership.
Houlston said that Select & Save could now operate in a wider area of the country. The group has recently expanded beyond its Midlands heartland to open stores in London and Havant in Hampshire.