Number of teachers is not the issue
I do a lot of STEM work and I am quite passionate about improving STEM education in school, especially in CS.
So increasing the number of CS teachers sounds great, but there are caveats. Firstly where are they to come from. Not from industry, who are struggling to recruit themselves and why would a CS grad want to to take a job with long hours, bureaucratic pressure and poor pay. The desire to make a difference to the next generation only goes so far.
The truth is announcing 8000 new teachers seems akin to the Soviet Union announcing tractor production targets
Then there are the schools themselves. STEM subjects are expensive to teach. They need extra resources that have to be bought out of schools stretched budgets. Therefore while many schools pay lip service to teaching STEM, most do the bare minimum. It does not matter how many STEM teachers there are, if the resources are not there to teach them effectively. While some schools have the resources to do an effective job, this is uneven and most rural or inner city schools just won't be able to do it
So here are my solutions.
Stop mucking about with ideological led programs such as free schools and the return of grammar schools and put the resources into existing schools instead.
Provide extra funds for basic STEM resources. including improve STEM teacher pay and reduce paperwork. This will increase retention
Encourage and incentivize business to form partnership with schools. I know many of my colleagues who would be happy to do joint programs with schools, but barriers at both the buisness and school level make this very hard
Make sure you have a long term strategy in place and keep to it. The Micro:Bit debacle shows what happens if you don't do that
Finally and most importantly, stop some of your government ministers undermining scientists from undermining science and scientists by playing to the post-factual crowd. It erodes the public's respect of science and make it harder to encourage kids to take it up as a subject