The origin of the products on British shelves could change as retailers adjust their supply chains following the UK's vote to leave the EU, finds new research published by the British multinational banking and financial services company Barclays.A survey of retailers carried out after the EU referendum, shows that many are already reviewing how their supply chains operate, as a result of the vote to leave the EU.Retailers are looking to build more efficient supply chains (76 per cent), and are considering changing suppliers (30 per cent) and sourcing from different countries (28 per cent).In a potentially positive sign for the British economy, a third of retailers (32 per cent) predict that they will source more from the United Kingdom, with only 12 per cent expecting a reduction. Asia could also be a winner; 52 per cent expect to increase supply chain activity in India and 43 per cent in China. Consumers can expect to buy more products with an African supply source (38 per cent), but Europe fares less well, with 43 per cent of respondents anticipating a reduction in what they source from the region.As might be expected following the recent moves in the currency markets, foreign exchange concerns are high on the list of supply chain considerations. Four in five retailers (81 per cent) expect the effect of Brexit on foreign exchange rates to have a negative impact on their supply chain and 70 per cent will be reviewing their currency hedging strategy in light of the referendum result.