To be scrupulously fair it is not her ability to wow me in interviews that will convince me of her competence (or not) as a politician. Politicians are supposed to be the representatives of the people - not experts but educated, reasonable people with an overview - the ability to make decisions based on the options available and a reliance on policy advice from people who can do big sums is a requirement.
I have worked in local government and the politicians I had the most respect for were the ones that listened and understood their role and took it seriouslyand were thoughtful about the impact of a decision. They needed people to do the research, costings, finding budgets and making policy and writing speeches. I don't need a politician to be slick and shiny as an oil spill, and media trained till they sound like policy robots I want them to be real and credible.
Dianne Abbott is real but not always credible. I don't have much time for her but she is to be admired or at least acknowledged - (not sure I am would be so laid back if she was my MP of course!
) - for her longevity in the cesspit of parliamentary politics.