"It's possible," said Martha, and took a sip of her drink thoughtfully. "I've done it. Admittedly, without any intention of doing so, so I can't really give any advice on how it's done..." Her expression indicated that she sure as hell intended to figure it out, though.

Home Counties, definitely, though with a faint American tinge? Maybe Martha was losing her touch--the Doctor would know, but the Doctor always bloody knew.