Playing at leapfrog Eroski Grupo is raining on Carrefour's parade as it makes its way along the motorway in the Basque region of Spain. Anne Bruce looks at its offer Rivals Carrefour and Eroski Grupo are staking their claims to the Basque heartland of Spain. But as they leapfrog each other along the line of the main motorway towards the French border, each contrives to keep a respectful distance apart. Eroski, the biggest grocery group of Spanish origin, is the retailing arm of Mondragon Corporation Cooperativa. Formed in 1998, it is the result of a merger between the co-operative Eroski, active in the Basque region, and Consum S Co-op, operating in central and southern Spain. With 44 hypermarkets and 760 Consum branded supermarkets, it claims a 12.1% share of the Spanish market, according to IGD data. But it is multi-national Carrefour which is king of the road, with 141 hypermarkets, and a 26.2% share of the country's grocery market. Eroski is going full throttle to catch up, having added 528 supermarkets to its portfolio since mid-1998, and made recent developments to its network in south-west France. An expansive Eroski hypermarket enjoys dominance in San Sebastian, although Carrefour recently created a stir when it opened on the other side of the nearby border with France, leafleting the homes of Eroski customers, and lionising some of the trade. The San Sebastian hypermarket is located in the Garbera retail park close to other leading retailers which include Toys R Us, Body Shop and Etam Lingerie. There is an array of restaurants and other attractions where visitors can relax after shopping. The park also houses an Eroski petrol station where business must be lively since there are cars and vans parked as far as the eye can see. Just getting through the outskirts of the retail park to the hypermarket at its core, is quite a trek for any shopper. On their approach, they are welcomed by a bank of 50 tills stretching along an open frontage to the hypermarket. The tills separate it from the comparatively diminutive attractions of the shopping centre and look like a customs check point between two states. Inside, the hypermarket has the buzz of a bazaar. Eroski piles high and sells cheap anything from mattresses to CDs. Eroski's slogan is "Satisfaction en qualite et prix" (satisfaction in quality and price) and it will continue to be able to provide both with its recently launched online service, as it chases Carrefour into cyberspace. FIXTURES AND FITTINGS - The store is 41,000 sq ft - Opening hours: 10am-10pm Monday to Saturday - Group turnover: More than 600bn pesetas (£2.27bn) in the last financial year {{SPOTLIGHT }}