If Julian Coman is old enough to remember the privatisation of British Gas ( Reversing Thatcher’s failed legacy of privatisation can be a Labour vote-winner. If you see Keir, tell him, 5 May ), he’ll surely also remember the running national joke that was British Rail, or the six-month wait to have a landline installed by the publicly owned British Telecom. His “private ownership bad, public ownership good” analysis overlooks the key point that, under either ownership model, what matters is the level of investment in the service. Pressure on regulators by successive governments to suppress investment allowances in the interests of keeping down utility bills has dwarfed the behaviours of some owners as factors in determining service levels. To argue that renationalisation will deliver substantial improvements requires one also to identify where in its over-stretched budgets the government will find the billions of pounds of extra investment on top of those currently being provided by private investors.…