The likely culprit is more likely to be Southwarks maintenance strategy rather than poor workmanship - pavement maintenance is relatively straightforward, workmen are generally skilled, and modern materials pretty forgiving. When budgets are tight a reactive maintenance strategy is more likely - patching up problem areas as and when they get so bad local residents start to complain. Unfortunately, patching is a short-term fix and solving the underlying problem - by replacing the pavement in its entirety, not just the top layer - represents higher up-front investment. Although this approach would likely pay for itself in the long term.