“Ultimately, the court conducts a general appraisal of the position having regard to what is reasonable for both the paying and the receiving parties. This normally involves an assessment of what is reasonable having regard to the class of litigant to which the relevant party belongs, rather than a minute assessment which it would be inconvenient and disproportionate to undertake. In commercial cases the rate of interest is usually set by reference to the short-term cost of unsecured borrowing for the relevant class of litigant, though it is always possible for a party to displace a 'rule of thumb' by adducing evidence, and the rate charged to a recipient who has actually borrowed money may be relevant but is not determinative. See F & C Alternative Investments Ltd v Barthelemy (No 3) CA [2013] 1 WLR at paragraphs 98, 99 and 102 to 105; Bim Kemi AB v Blackburn Chemicals Ltd[2003] EWCA Civ 889 at 18 and for example, Fiona Trust & Holding Corporation v Privalov[2011] EWHC 664 (Comm) .”
“48. However, the possibility of inferring tacit approval, and therefore of establishing the existence of a consensus to cooperate rather than compete, depends on the context of the communication. 49. First, where an undertaking receives information relating to an illicit initiative and does not oppose it, its acquiescence in that initiative may be inferred from the absence of response, provided that the circumstances are propitious to the formation of a tacit consensus. The lack of opposition to an illicit communication is reprehensible because, under certain circumstances, mere lack of reaction from the addressee will lead the other party or parties to believe that the addressee subscribes to the illicit initiative and will comply with it. Therefore, in order to infer knowing participation of the addressee in a concerted practice, the context of interaction must be such that the addressee may be deemed to appreciate that the competitor will consider its silence as an approval and will rely on mutual action, even in the absence of response.”
“Where it can be established that such undertakings successfully concerted with one another and remained active on the market, they may justifiably be called on to adduce evidence that that concerted action did not have any effect on their conduct on the market in question.”
“In that regard, it must be stated that probative data illustrating the competitive nature of the market and, in particular, the decrease of prices during the period concerned cannot suffice, of itself, to rebut that presumption. That data does not of itself make it possible to prove that that undertaking did not take account of the information exchanged with its competitors in determining its conduct on the market. It follows that that data does not of itself preclude the presumption that the concerted action enabled that undertaking to eliminate uncertainties regarding its conduct on the market, so that normal competition might as a result have been prevented, restricted or distorted.”