48 years old - no pension. Advice.

I'm 48 and just moved back to the UK from abroad. Decades of living as if the future does not exist means that I have no pension and have not been making NI contributions (in my defence, moving back to the UK was not on the cards twenty years ago).

I would love some advice about what kind of pension/saving scheme would be best for me. I am self-employed, just starting out building my business. Thanks.