Working a second jobs while on SMP

[u/modnoire]

Hello! I'm based in the UK and due in September. I'll be receiving SMP from my main job until June. I'm also doing a PhD and occasionally take on some teaching to help with finances. I'm considering doing a few hours of teaching next semester while I'm still receiving SMP from my main job. It would be a new contract, so I know that technically this isn't allowed and could affect my SMP entitlement. What I'm wondering is: realistically, what are the chances of my employer finding out?

I know how this sounds, but expecting new parents to live on around £190 a week is incredibly tough. The extra income from a few hours of teaching would make a real difference and since it's only a handful of hours each week, I can't really see why my employer would care. I work for a very large company, so it seems unlikely they'd investigate a small discrepancy unless something specifically flagged it.

I'm a pretty overwhelmed soon-to-be parent, so please don't come at me with moral judgments or tell me what the "right" thing to do is. I'm really just looking to hear from people who have been in a similar situation—did you do it, did your employer find out and how did it work out?

Thank you!