Where to buy maternity clothes in London?

[longwayaway]

I'm going to be in London this weekend and I'd like to buy some maternity clothing - in a real shop, not online! i.e. I know that H&M has a maternity line, but is there a particular location where they carry the maternity stuff on site? (Because they don't in my town!)

If you know for a fact that a particular store at a particular location has maternity clothes on site, can you please comment here? Happy to hear recommendations for maternity-only shops as well as bigger stores with maternity sections.

There's not as much as you'd think unfortunately!
If you are doing Oxford St, as others have said there's:
Top shop Oxford circus. The maternity is in a side entrance
H and M regent Street
Debenhams
I think (but not sure) that new look, primark and gap might have some but not checked recently.

Some shops you'd think would have it but DON'T are John Lewis (I spent ages looking for it) and Dorothy Perkins.

You might need to do some googling to see what shops are there but some of the nice areas a bit further out might be a calmer shopping experience
Angel has H and M maternity and there used to be a boutique shop on upper street but not sure what's still there.
Hamstead might be worth a look too

New Look Oxford St doesn't - I spent a good 20 minutes scouring the whole 5 s floors and nada!

Another vote for seraphine here, they have beautiful stuff. There's one on kensington high street where you can also get not-strictly maternity wear but nice stuff that is stretchy and fits from M&S, gap, etc, and then hit up whole foods and feel virtuous about your tasty organic lunch!!!

Primark opposite Tottenham Court Rd has maternity range on the 2nd floor. Nice solid jeans, underwear & hoisery, but I prefer the t-shirts & sweater/sweatshirt dresses from H&M for the quality & style, also on Oxford street if you walk towards Oxford Circus. River Island otw has quite fashionable numbers but are pricier.