It's meant to be a Manchester one but it's not very good... Probably a combination of the fact Jane Leeves is from Essix and she's lived in America for a long time...
I'd always thought it sounded passable, but then again I'm terrible with accents: considering I used to work with a woman from Manchester who sounded nothing like that, you'd think I'd know better! Then again, everyone gets my accent wrong so it kind of evens out: it's so bad that the person I met a couple of days ago who correctly identified where I was from really surprised me (for the record, it should be like the aforementioned Cheryl Cole's, but it's got a bit mangled due to living elsewhere.)