Well, I'm no apologist for the New Labour government which, despite two landslide election victories, failed to achieve very much at all apart from kow-towing to the USA and its crazy president. It depends on your definition of infrastructure I suppose, but I have to admit that the Labour governments did have some positive achievements including the largest hospital building programme ever with over 100 new hospitals opened, and over 4000 schools were rebuilt or refurbished. Both infrastructural improvements were greatly needed and had been avoided by preceding Tory governments.
I'm struggling to find much else though. They failed to support the Severn Tidal Barrage which would provide renewable energy for decades to come. I suppose Labour's White Paper on airport development from 2003 expressed support for runway extensions and terminal developments at several airports including Bristol, Stansted and Teesside - but then, as far as I'm aware, no finance was provided to support any of these developments. Hopeless.