Employer's NI - Calculated on Taxable Income within Tax Year or Simply Pro Rata?

Hi

I haven't worked during this tax year and I want to incentivise my employer to pay me up to the 43k allowance so that I can take maximum advantage of the tax basic rate (20%) of tax during tax year 16/17, of which I would have 3 months remaining in the tax year from when I start work in January. To clarify, I would normally fall into the Higher tax band for my full salary.

My question is: Is Employer's National Insurance Contribution aligned to the employee's taxable income within a tax year or simply calculated pro-rata regardless of taxable income?

Therefore, would my employer reduce the Employer's National Insurance Contribution amount payable by paying me more during the 16/17 tax year (and subsequently reduce my salary in 17/18 tax year to reflect)?

I'd like to know if this would be a mutually beneficial arrangement or whether I would need to offer to reduce my salary by a small amount to make it mutually beneficial.

Thanks for advice in advance