Applying for art foundation (sans A-level)

Hello, thank you for reading. I did not take art A-level or any other art subjects, all of my subjects are humanities. My grades should be quite good, but this isn't too helpful if I want to apply for art courses. I am a very indecisive person and I didn't really allow for this.
So I find myself needing to get together a strong portfolio. I have some pieces that I've completed in my own time, but not enough, and not made with portfolio work in mind. I'd like to apply for foundation at a university where I would be happy to go onto study fine art, ideally.
I think it would be wise to take a gap year after A-levels and apply during this (so not for deferred entry), in order to have time to complete more work for the portfolio - although I don't think my college would be best pleased.
Any advice is welcome! If anyone has done a similar thing themselves, or knows of someone that has, that might be helpful. Thank you.

One of my students took all the right A levels for medicine and then realised she really wanted to do interior design. She got a place on an art foundation course at her local college without too much difficulty on the back of her portfolio. She went on to somewhere more prestigious for her degree. I suggest you may have more luck with a local college than an art school without A level, but once you've competed your art foundation, you can apply anywhere on the same basis as anyone else. It does all depend on the portfolio and it doesn't matter where you do your foundation. Art schools are not snobby about this. They know that the majority of people do the course locally because it carries no entitlement to student finance and have to stay at home to save money.

Oh, thank you! It's reassuring to hear that this is possible at all. Schools say that exceptions may be made to entry requirements if the student presents strong potential and enthusiasm, but it still felt like something that just sort of doesn't happen. I'll definitely consider local colleges - although, finding time for portfolio work between studies is still a worry. There will be less competition, so I won't have to work quite so hard, but there is still much to be done considering I'm playing catch-up.