Thanks Keith that is really useful.
I actually earned £500 for that one day's work in March. If I do enter it in my 14/15 tax return is there a correct way of entering it on my tax return, without declaring myself self employed?
I have not looked into JSA yet but think I will have to.
I would be inclined, as it is a one off, to include it under Other UK income not included on supplementary pages as 'Other Taxable Income.' Don't forget to include any deductible expenses from the 500 quid you earned in the adjoining box. You will find the relevant boxes immediately after the pensions income section. You can always make a note at the end of the SA100.
You should telephone your local Job Centre immediately, declare yourself as unemployed and sign on for the allowance. with respect you should have done this on 10 April.
Thank you for your support.
Thank you Keith!