I hadn't seen Starmer's popularity explicitly broken down by occupational class, so I decided to compare Starmer, RLB and BoJo across NS-SEC analytic classes using BES Panel survey data:

Boris is more popular than Starmer among working class respondents (classes 5-7) and Starmer is very popular with the middle class, especially the newer 'service class' employees in classes 1.2 and 2. RLB is less popular than Starmer overall, but the gap is smallest among the WC

Labour's electoral coalition has shifted over time. In the 40s and 50s is mostly relied on manual workers and lower supervisors (5-7). In the 60s and 90s it picked up middle class voters (1.2-2/3) as well, and in the 00s and 10s it began losing working class support.

My biggest worry with Starmer is that he will not be able to reverse this trend -- both because I think it's morally reprehensible if Labour can't gain the support of the people it exists to represent and because I think we can't win without both sides of our electoral coalition.

I've also run the numbers by region, with some interesting results. Starmer is more popular than Boris in the North East, North West, Yorks, but less popular in the Midlands. He's also well-liked in Scotland and Wales (encouraging news!) and (unsurprisingly) loved in London