Lucy Griffiths showed her arse but kept her bra on in a sex scene in the first episode of True Blood. Sophie Rundle had a spectacular and long topless scene in episode 6 of Episodes. Clips are online of both of them.
Thanks to various commentors for updates, Michael D says that In Deadtime, Emily Welch, Alex Marieka Hanly and Elle Wood are topless. I listed Tanner Hall as a prospect last time, no nudity in that from any British actresses. BBC Watcher said that there was a semi-nude scene in a recent episode (the second) of Live At The Electric, this was an unidentified actress walking around with her arse out.
There's been no nudity in Bedlam series 2 so far and I don't expect any. There was nothing in episode 1 of True Love.