Free School Meals can only be awarded if you or your partner are claiming either:
Income Support
Income-based Jobseeker's Allowance
Income-related Employment and Support Allowance
Support under Part 6 of the Immigration and Asylum Act 1999
The guarantee element of Pension Credit
Child Tax Credit, provided you are not also entitled to Working Tax Credit and have an annual gross income of no more than £16,190, as assessed by HMRC
Working Tax Credit run-on - paid for 4 weeks after you stop qualifying for Working Tax Credit
Universal Credit - if you apply on or after 1st April 2018 your household income must be less than £7,400 a year (after tax and not including any benefits you get)