Instructions phrased as requests.

[Dilbertian]

In our British style, we often phrase instructions as requests or questions. Grammatically, such sentences should finish with a question mark. But when it's not actually a question but an instruction, is a full stop acceptable? Or an exclamation mark for urgency? Or some combination?!

Could you let me know as soon as possible.
Could you let me know as soon as possible?
Could you let me know as soon as possible!

The first one is fine. Second sounds like they have a choice, third like a frustrated demand!!

I stopped phrasing instructions as questions many years ago. I once asked someone 'would you mind doing x?' and they said 'yes I would'. I then had to tell them that they had to do it anyway, which was a bit awkward!

I would end 'Please let me know as soon as possible' or 'I'd be grateful if you could let me know as soon as possible'. And if I was at work I'd probably give them a fixed deadline rather than say 'as soon as possible'.

Having said that, if I was going to stick with a question I would include a question mark.

Don't phrase it as a question if it's an instruction. Problem solved!