I need to pick mumsnet's brains 
I have a zero hours contract with an employer who only needs me weekends. I've been offered another relief post with an employer who needs me mon-fri only. I'd like to work both places because they don't clash and I need both to get a decent income from it.
Are there any tax implications? I don't know how much I need to earn before I pay tax, let alone if I'll be tax more because I have two jobs.
Can anyone offer advice? 