What do we do about the fact that within countries, some places are doing so badly, even when the national economy is doing pretty well? In the US, people are worried about the post-industrial heartlands. In the UK the deepest problems seem to be in old seaside towns like Blackpool. Andy Haldane, chief economist at the Bank of England, has been thinking a lot about this question. He's been touring some of the poorest parts of the UK and he spoke to the FT's Sarah O'Connor after one of his recent trips.