I'd suggest a Panasonic G3. They're well cheap right now
(£210 on Amazon as I write this, with the kit lens that apparently has negative cost, since the body by itself is £277), which leaves you a bit spare for a nice lens (
tele-zoom,
pancake or maybe
portrait) or what have you. You probably won't gain much by getting something more expensive, at least not up to £400 – mirrorless cameras tend to be rather more pricey than DSLRs.
edit: the G3 might look big like a DSLR
but it really isn't.
EDITED: 8 May 2014 23:18 by CAER