In the long run, the Labour party suffers from unavoidable voter attrition among older voters. In every generation as people grow older, they become more economically and socially conservative. As they accumulate wealth, redistribution becomes less appealing, unemployment less of a threat and inflation more frightening. Social liberalism also becomes jarring. While societal change is stressful, it is especially disruptive when we get older. Studies reveal that as we age we become less intellectually curious, less tolerant of ambiguity and less tolerant of change in our environment. This conservativism is even deemed to reduce stress among older voters.

In the past, this voter attrition was mitigated by partisan loyalty. However, after decades of declines in party identification and the relevance of social class, it has become more difficult to hold on to these voters. Merely maintaining the party’s level of support requires replacing these lost voters with new ones. In contrast to the older demographic, the party’s core policies are most attractive to those under 45 years of age. The challenge is to repeatedly and comprehensively win over these voters; the party must capture the zeitgeist of each generation as it comes of age. This requires repeated reinvention, and requires the party to be the vanguard of economic and social progress.

There is no longer a homogenous group of 'working-class' people with the same titles, pay, conditions and lifestyle

Centre-left parties have, in many cases, ignored this necessity at their peril. They have focused on their existing coalition while hoping the prevailing economic winds might blow in their favour. They have allowed their focus on “equality” to slip from wealth and income inequality to identity politics, which yields little concrete support and necessarily alienates them from their base. The decline of the centre-left across Europe is in sharp focus in France, Germany and Italy.

In Britain, the necessity for repeated renewal is represented not only by Tony Blair’s “modernise or die” mantra but also the change under Jeremy Corbyn. While a different generation needs a different message, the importance of appealing to a new generation is consistent across both leaderships. It is clear that Corbyn has managed to reconstitute the Labour party as representing younger voters defined by being on the left and against the current trajectory of Brexit.

While this coalition needs to be targeted with emphasis on the left and on remain, party strategists and MPs will continue to be haunted by the “former Labour voter”. This is a risk. Focusing on the voters the party will (unavoidably) lose rather than the ones it could win paralyses the dynamism required for the party to convey a coherent message. One infamous example of this under the Ed Miliband regime was his turn towards a restrictive policy on immigration, which only served to undermine his authenticity.

‘Deep down, the Labour party has a sentimental attachment to the notion of representing the working-class voter.’ Voters at a cotton mill wait to be addressed by a Labour candidate in Rochdale, 1958. Photograph: Jane Bown/The Observer

Deep down, the Labour party has a sentimental attachment to the notion of representing the working-class voter. This undermines the party’s dynamism. It is not the noble cause of seeking to represent ordinary people on lower pay that is foolhardy, rather the hypothesised notion of a homogenous working-class voter. To a pollster, it is clear that social class is an archaic classification that bears little resemblance to the complexities of post-industrialised societies. Put simply, there is no longer a broad homogenous group of “working-class” people with the same titles, pay, conditions and lifestyles dictating their social attitudes. When baseline personality traits drive attitudinal differences within social classes, it is clear that it is impossible to capture the demographic group that effectively no longer exists.

Undoubtedly, the Labour party can and should still target voters with poor working conditions, rights and prospects. Indeed, there is plenty to oppose in the context of global capitalism in the 21st century, including the impact of automation, unregulated labour markets, weak regulation of financial markets, rampant global inequality, and chronic housing shortages. Furthermore, there is a moral imperative to do so that is fully in line with the values of the Labour party. However, these issues align more closely with younger voters who, as it stands, according to the Resolution Foundation, are the first generation expected to earn less than their parents. These voters also overwhelmingly voted remain.

The most recent election successes in Kensington and Canterbury have undoubtedly caused an unease among those with notions of what the Labour vote “should be”, with particular concern for the type of voter the Labour party is attracting under a potential policy of opposing the current trajectory of Brexit. However, these constituencies represent a very small proportion of the Labour vote. The leftwing credentials of Labour remainers (those who supported both Labour and remain in the 2016 and 2017 elections) are in fact no less pronounced than those of Labour leavers. Indeed, evidence from the British Election Study indicates that, on average, Labour remainers place themselves marginally to the left of Labour leavers.

Indeed, they are also just as likely to disagree with the notion that private enterprise is the best way to solve Britain’s problems, and just as likely to agree that major public services and industries should be in public ownership. While some traditional heartlands are now more difficult for Labour is partly the result of the decline in importance of social class and part the result of the ageing composition of those constituencies as a consequence of the wave of urban migration that followed the global economic crisis.

It is undoubtedly the case that the Labour party’s future is, as always, with younger voters and, at least for a short time, in the context of the UK leaving the EU and the problems faced by those under 45, the party should seek to represent those views. After all, it is also abundantly clear that Labour remainers are far more concerned with Brexit, while Labour leavers are not.

• Kevin Cunningham is a former targeting and analysis manager for the Labour party