A recent British case, Nigel Witham Ltd v Smith & Anor (No 2)  EWHC 12, has determined that a successful party who unreasonably delays consenting to mediation until a very late stage so that the chances of a successful mediation are poor may be subject to an adverse costs order.
"Case law: delay in consenting to mediation,"
ADR Bulletin: Vol. 10
, Article 3.
Available at: https://epublications.bond.edu.au/adr/vol10/iss4/3