Were they vastly different? In economic terms, Blair and Brown had largely pledge to follow the Tories' existing spending constraints and were also strongly pro-free-market. The differences with the Tories, at least for the first few years after 1997, were largely to do with competence, not having a set of MPs that seemed to be continually at war with themselves, and a relatively lack of corruption scandals. Plus rhetoric that was more green-friendly. As I recall, the only significant policy differences from the Tories were Blair/Brown's commitment to introduce a minimum wage, devolution for Scotland and Wales, a settlement for peace in Northern Ireland, and moving forward on gay rights. In fact, take away those few specific policy differences (which were in any case responses to the situation in 1997 and would not be particularly relevant today) and that all looks remarkably similar to the 'change' Keir Starmer is offering today.