History degree to become an investment banker?

Yes, you can go into investment banking with any degree, provided you did it at a target university. If you do history at Oxbridge/UCL/LSE then you've as good a chance as anyone else at those unis.

Could I get into investment banking through a law degree too? If it is at one of the top universities for example Cambridge,LSE etc

What does "any degree" mean?

I did not choose to do A Level maths however still want to pursue a career in the economic/banking side of things. I was wondering if a degree in history would allow me to access this pathway to eventually become an investment banker. Is this still viable?

I would question why you are considering doing a History degree if you want to go into Investment Banking. Investing is all about calculations: trends, risk, predictions and margins etc. so it may be difficult to showcase that side of yourself. There is big competition for those lucrative salaries in top companies!

If you are certain you want to be an investment banker, then why not look at the companies you want to work for and see what their entry requirements are AND have a look on LinkedIn to see what degrees their employees have. It will give you a realistic idea of which degrees are successful hires.

Good luck with your decision