Experimental recordings of RP-speaking Cambridge University undergraduates has indicated that after coarticulatory effects are taken into account, words such as "bag", "that", "gab", "Ann", "ban", "damp", "mad", "bad", and "sad" may have slightly longer vowels than relatively shorter words such as "lad", "snag", "pad", "Pam", and "plan". However, no evidence of consistent duration differentiation was found in the possible minimal pairs "adder"/"adder", "cad"/"CAD", "can" (noun)/"can" (verb), "dam"/"damn", "jam"/"jam", "lam"/"lamb", "manning"/"Manning", "mass"/"mass", "sad"/"SAD". This casts doubt on its status as a true phonemic split, and has been described instead as diachronically stable, lexically-specific sub-phonemic variation.