Plan B-the musical alter ego of English film actor Ben Drew -debuted in 2006 with “Who Needs Actions When You Got Words,” a post-Streets rap album notable for the inclusion of a Hall & Oates-sampling cut titled “Mama (Loves a Crackhead).” But on his latest album, “The Defamation of Strickland Banks,” Drew cleverly reinvents Plan B as a big-city retro-soul singer, a la Amy Winehouse or Daniel Merriweather. Last year, the set entered the Official Charts Co. album tally at No. 1 and has since been certified triple-platinum in the United Kingdom, thanks in large part to the exceedingly “Rehab”-ish hit single “She Said.” Given Adele‘s huge success on U.S. shores with her recently released “21,” “The Defamation of Strickland Banks” seems well-positioned for an American breakthrough, even if the concept album’s thorny storyline (in which Drew’s alter ego embodies yet another one) puts off casual R&B fans. Listeners in that category should check out opener “Love Goes Down” and “Stay Too Long,” a jumpy garage-soul gem that Raphael Saadiq might admire.