The Met Police have proven to be corrupt over many years, here's just one example. There are many more if you care to look.
https://www.bbc.co.uk/news/uk-60832186
That said can the majority of the Met be called corrupt? Personally no, certainally at the lower levels and I knew a few of regular officers when I lived in the Met area for a few years (I framed a few advanced driving certificates for some of them). They had no respect for their superiors.