Thames Water , with occasional cameos by ugly little siblings Southern Water and South East Water , grabs most of the attention in the sector for obvious reasons. So it’s easy to overlook what’s happening further north. Short answer: the new era of higher bills and higher spending on water infrastructure will feel splendid if you’re United Utilities, licence-holder in north-west England, or Severn Trent, operating in the Midlands. The former’s share price surged 11% on Thursday, the sort of thing that shouldn’t happen at a utility where success is meant to be defined in terms of dull predictability. And it’s definitely unusual to see a one-day valuation jump of that size when the company is issuing £800m-worth of new shares. Indeed, there was a mini-stampede for UU’s equity after Australia’s sovereign wealth fund, Future Fund, and the global infrastructure investor Atlas grabbed half the allocation in the placing as “cornerstone” investors. Why the rush?…