The contractor has branded the council 'uncooperative, unprofessional and underhand' in a statement released on Monday (11 April).
A Mowlem spokesperson used the opportunity to unveil the firm's plans to commission an independent condition survey to establish accurately the condition of the spa when it was handed over to the council, specifically in the case of contentious issues such as the spa's steam room floors.
The spokesperson wrote: 'We have offered the council the opportunity of conducting a joint survey, but it has not so far accepted our offer, which nonetheless still stands.
'This is symptomatic of the uncooperative, unprofessional and underhand manner in which we feel the council has conducted itself throughout the project; the most recent example being its attempt to remove us from site on the pretext of us refusing to comply with an instruction, in the full knowledge that we were indeed carrying out the work requested.
'We would emphasise that it is Mowlem that has decided to vacate the Bath Spa site and that we are doing so while reserving all of our rights.
'We remain certain of our position and, having taken specialist legal advice, are confident that the costly and lengthy round of legal disputes to which the council now seems to have condemned itself, and the council taxpayers of Bath, will go in our favour,' the spokesman added.