winjim
Smash the cistern
Many NHS trusts are currently in the process of vaccinating non-patient facing and non-clinical support staff.Presumably that would be "patient facing" or "front line" Contractors, not Contractors as in building workers, which is, I believe, from his post, what @midlife was referring to.
However, one simple explanation for the Building Contractors @midlife saw in the queue, may be that there were "no shows", or some other reason why Vaccine doses need to be used up, before being wasted, and, the Building Contractors were "available".