Please help in upgrading old NOKIA 3310 on 02 PAYG

Patr100

I've had a Nokia 3310 on O2 for about 10 years or more that has served me well as I only needed basic functions for ocasional use .
Now I would like to find out about upgrading to a megapixel camera phone, preferably with an email function (but I don't desparately need full browsing) . I can actually check and send my hotmail email using texts currently but the memory is so tiny I need to upgrade soon.
Ideally, want to keep my current mobile number and stay with 02 as I get a good homebroadband deal and use the money saved on texts
So in summary:
Want to keep existing PAYG O2 mobile number.
Megapixel phone (not essential but would be nice).
email function compatible with hotmail (if poss though can use current text only option)

It's been so long I haven't kept up with upgrading choices while also keeping the same number. What are my options?
Any advice appreciated.