British shop price inflation sped up in May on the back of disruption and higher energy costs caused by the Iran war, according to a retail industry group which said the government had to do more to keep costs down. The British Retail Consortium's monthly survey of major chains published on Tuesday showed that prices in May were 1.2% higher than a year earlier, up from a 1.0% rise in April. Food price inflation slowed to 2.7%, its lowest in a year, from 3.1%.