Inadmissible on any substantive issue but can be produced to court when considering cost. Here, it was held that the earlier refusal of a settlement offer can make the losing party liable for costs. The name itself comes from the famed case Calderbank v Calderbank. This is particularly relevant if you reject the offer and the other party is successful at trial. If you have, important to understand what it means. Preview text 1 Calderbank Offer If involved in a legal dispute, you may have come across a Calderbank Offer.