In just the regular (non-maternity) section H&M have got a heap of spaghetti strap vests for £3.99. Very long (so will easily cover a bump), and absolutely perfect to go under a pregnancy wrap top like the Jojo ones.
They've got black, white, purple, dusky red, green, dark grey, lighter grey (and maybe a couple of others I can't remember).
Best part is that the straps are adjustable so can be tightened to ensure coverage of a hideous maternity bra (as most of them seem to be!
)
Just thought I'd pass on as it's great to find a handy piece of clothing when pregnant.