We should have a sense of perspective about Labour’s position today. The Labour party – for the 20th century one of the least successful social democratic parties in western Europe – has become one of its most successful at the beginning of the 21st. Tony Blair’s unparalleled vote-winning capacity, but also his government’s performance in office, are viewed with considerable envy in Europe and beyond.

Why did the social democratic left need to change? Social democracy and its institutions – the monolithic welfare state and Keynesian macro-economic policies – had reached the end of the road in their postwar form by the late 1970s. While refusing to recognise this, Labour came near to casting itself into oblivion. By the early 1990s it was accepted that Labour had to embrace a new model. Five strategic ambitions flowed from this and were central to the party’s march back to power in 1997.

First, that Labour stands for social democratic values, but it separates means and ends and is therefore innovative in the means of delivery. Second, Labour marries its commitment to social justice through collective action with its belief in individual freedom through the market. Third, Labour combines policies for wealth creation with a commitment to fair outcomes and distribution. Fourth, Labour must recapture territory occupied by the right and reinterpret it for progressive ends – for example crime and immigration – and, fifth, Labour must engage with dynamic and emerging currents in British thought and society – environmentalism and consumerism are examples.

Since Tony Blair became leader in 1994, his and Bill Clinton’s conceptualisation of centre-left politics – known as the Third Way – has established itself as the central point of reference for debates on the left from Europe to Brazil to China. Third Way politics is essentially about the reform of civic and social institutions to ensure they provide opportunity and security to all, not just a few, in a world of change.

This is about renewing the left, not abandoning it. But it also means moving beyond the old solutions of left and right, and ensuring sectional and producer interests no longer hold sway. Where social democratic parties stick to the course of modernisation and reform – and maintain unity – they succeed. Where they diverge, they often lose direction, quickly get into difficulties, drift, and run out of steam.

Sticking to the course, however tough the challenge, is the underlying lesson of New Labour and Tony Blair’s success since 1997.

But there is a second lesson. Politics is a dynamic process. We do not fight subsequent elections on the battle plans and policy programmes of those we have already won. The task of the left is not merely to consolidate and reassure – our politics will only retain relevance if we are prepared to push on with new reforms that address the challenges of the future.

We are seeing this at the moment with the new politics of insecurity. This is not merely a question of employment security, an issue highlighted in the early years of the Clinton administration. Insecurity brackets together issues of crime, public services, finance and pensions, identity, terrorism and foreign policy. The right in Italy and Austria has exploited this powerful cocktail ruthlessly. The Conservatives are trying to do so in Britain. It is essential that theleft defines and addresses this challenge in its own terms.

Two next steps are essential in this context. We need to rethink the role of the welfare state in the context of changing family and employment structures to give greater security to working families. And we need to face up to the challenge of multi-culturalism and migration where communal values that sustain solidarity are under threat.

We benefit from migration, but we have to recognise the real strains that migration can pose on disadvantaged communities. Perceptions of unfairness can easily arise in relation to access to public services and benefits and are felt most strongly by those for whom life is a struggle and who work hard and play by the rules. Proper conditions need to be applied to new entrants seeking to gain citizenship status in the UK, ensuring they work in essential sectors where skills are scarce. In addition, the case for a technology-based ID system in an era of unprecedented human mobility has become incontestable.

New Labour’s challenge is fundamental – to maintain and renew its political definition in government. This means ensuring that our policies and programmes are seen to be driven by our values so we remain an identifiable left-of-centre government, and not just a competent administration. If modernisation amounts to creeping technocracy, we will alienate first our key supporters and then members of the wider public. If we don’t define ourselves, our opponents will do so for us.

We have to stay in tune with a changing Britain as a new political landscape emerges – and should not be afraid to take on new ideas.

Three issues that are now high on the agenda that were little discussed when New Labour was conceived in the mid-1990s are early years education, the importance of owning assets, and increasing the supply of social housing.

We must come to terms with the fact that the efficacy (not the identity) of the nation-state is weakening and that social democracy increasingly requires an international framework to achieve its goals – that is why our place at the heart of the European Union remains of paramount importance.

The lesson for New Labour – one that other social democratic parties are starting to heed – is that only by constantly renewing its route map and moving into a more confident and progressive next phase can it achieve its political objectives for the country. The coming year will test our capacity as a political movement to move forward. In an election year, our discipline and unity will be at a premium – as will our intellectual resourcefulness.