Extra job - I'll have to declare this, won't I?

[starrychime]

I work normal hours in my main job, use up all my tax allowance in this and just pay tax normally via PAYE. I've been offered regular work which pays £300 per month and I'll be doing it in the evenings maybe 5 hrs a week, it's not for an employer as such but admin stuff for various colleagues. It'll be paid by personal cheque. So should I declare self employment for this job - it'll affect my tax credits I guess and will be taxed if I declare it so it's tempting not to but I'll really have to won't I?

Yes you need to declare it. It'd be worse if you didn't and were caught.

Yes, that would worry me constantly - I'm an honest soul I'll probaby need to buy a cheap laptop and a copy of MS Office for the job so am I right in thinking I can maybe claim that as exxpenses?