UNIONS, campaigners and MPs are demanding the government put an end to the uncertainty surrounding Thames Water and permanently nationalise the scandal-ridden utility.They renewed their calls to nationalise the water firm today after Environment Secretary Emma Reynolds came out against a £10 billion rescue bid, saying it poses an “unfair cost to consumers.”The minister’s warnings closely followed an open letter to Ofwat signed by 107 MPs demanding the government reject the deal put forward by Thames Water creditors to salvage the company.