the personal motor car and the introduction from the 1950s onwards of the American-originated supermarket format. The market shift in price and convenience led to the establishment of common trading brands operating as virtual franchises to win back the consumer, including: Budgens, Costcutter, Londis, Nisa and SPAR. There was also a consolidation of some shops under some larger corporate-owned brands, including One Stop and RS McColl. The primary competition to this privately owned 'corner shop' model came from the network of consumer cooperatives which were created after the success of that created by the Rochdale Society of Equitable Pioneers in 1844. Rather than being owned by individuals, these shops were owned by their customer-members and, owing to their popularity, the number of co-operative shops had reached 1,439 by 1900. Co-operatives came about as a response to the problem of adulterated food which existed at the time, and later they enabled members to buy types of food that they would otherwise be unable to afford. At their peak in the 1950s, consumers' co-operatives accounted for approximately 20% of the UK grocery market; however with increasing competition this has decreased to around 6% in 2015. Due to a number of mergers over the years, the grocery co-operative sector in the UK is now predominately composed of the national The Co-operative Group and a few large regional co-operative societies such as the Midcounties Co-operative and Scotmid. Today, the majority of food retailing co-operatives societies brand their convenience shops as Co-op Food, and together they form the second-largest convenience shop chain in the UK and the largest by number of shops, with one in every UK postal code. From the late-1960s onwards, many such shops started to be owned by expatriate African-born Indians, expelled from their homelands by the newly independent countries' rulers (see Expulsion of Asians from Uganda). Under the Shops Act 1950, Sunday trading had been illegal for most traders, with exceptions only allowed for small shops selling perishable items (i.e. milk, bread, butter, fresh meat and vegetables), and most shops that were not off licences (i.e. selling alcohol) had to close at 20:00. The Sunday Trading Act 1994 allowed large format shops over to open on Sunday and later extended to 24/7 opening. In more recent time, due to a combination of competition laws and a lack of large-scale development space, many of the larger retail brands have now developed shop