What do you mean there is no expedited security? Of course you get Sky Priority in DTW. Do you mean there is no Fast Track immigration at LHR?
Yes, sorry for the confusion. You do not get Fast Track at LHR. I find it extremely odd that Delta PMs get this benefit on VS but not DL, seems weird to get better benefits flying a partner. I felt the need to point it out because Delta CSRs seem absolutely clueless on the issue, both phone and twitter support told me otherwise before departure.