We already knew this. I'd have been amazed if Starmer had done anything other than totally ignore the fact that he's lost a whole section of the population.
Some figures for the loss of votes:
The impact of Muslim voters at the 2024 election was even bigger than you think
Labour lost more than 300,000 votes in areas with the highest Muslim populations, leaving it with fewer supporters overall than it had in 2019
hyphenonline.com
There was a dramatic Labour collapse in the constituencies with the highest proportions of Muslims. My own research over the last 36 hours has found that, in the 21 seats where more than 30% of the population is Muslim, Labour’s share dropped by 29 percentage points from an average 65% in 2019 to 36% in 2024. Turnout also fell more steeply than average (down 11.2 percentage points) in these seats, suggesting that some disaffected Muslim electors abstained while others voted for other candidates. In these seats, the total number of Labour votes fell from more than 600,000 in 2019 to just under 300,000 in 2024. That is the equivalent of more than half the total national drop in the Labour vote between the two elections (Labour has lost 537,688 votes compared with 2019).
The loss of Muslim votes was also a problem for Labour in some seats with smaller Muslim communities. In the 43 next-most Muslim constituencies (between 15% and 30% of the population), Labour lost another 300,000 votes. That means the equivalent of the entire national drop in Labour’s vote since 2019 happened in these 64 “most Muslim” seats.