Negative amount on the tax deducted entry for 'In this employment'

I'm filling in my tax return and on the section where I enter the details of the P60, the amount shown on my P60 for 'In this employment - Tax deducted' is in a negative but does not have an 'R'.
In the section of the self assessment online form where I enter the #UK tax taken off employer pay' if I enter it as a negative it gives an error message but also not sure if I should be entering it as a positive number?
Is this value tax that I have already paid from my PAYE pay or is it tax that I need to pay via self assessment?
Thanks in advance

Hi Matthew James
If you received a refund from the employer, after joining, then that employer would reflect the net tax deducted from you in that employment.
Please see the guidance at Self Assessment: Employment (SA102) notes pages Box 2on Page EN2 which will assist in the completion of your return.
Please ensure the correct box, for insertion of a negative figure, is completed.
Thank you
 

The value is tax you have already paid via PAYE. I can think of two possibilities: 1) Perhaps, on the particular format of P60 you have been given, the value has been rendered with a negative sign just in an attempt to illustrate it as deduction. (Employers are allowed to produce their own substitute P60s, which don't have to follow a particular layout so long as they contain the required information. They may have made a less than obvious design choice.) In this case, you would have an actually positive deduction to enter on the tax return. 2) Or, perhaps, you really did receive so much of a tax refund via your payroll, that it more than reversed all of the tax you ordinarily would have had deducted from your pay from this employment - meaning you genuinely have a negative deduction. This would be unusual. The online tax return site seems to think it's only possible with multiple employments in a year. A quick thing you could check to give you a hint one way or the other, would be to check whether you actually received more take-home pay, than your actual gross pay, for this employment. (I say hint, because other kinds of deductions like NICs or pension contributions might muddle the picture.) Or, you might be able to ask your employer's HR staff to help clarify the details on your P60 for you.