^that is after the the tax free allowance which will be something like £9500.
If your total earnings are equivalent to less than the tax free allowance (circa £9500) in the next tax year you shouldn't pay income tax
If you are planning on keeping the two jobs, you could ask for your tax code to be split between the two and providing you are under the tax free allowance you won't pay tax. If you don't split the tax code I believe you will pay tax at the BR code of 20% on your second job and then have to reclaim any overpayment at the end of the tax year. It has been a while since I worked with PAYE so I may not be up to date but I have split my code on my pensions and don't pay any tax.