25 What that affidavit evidence disclosed was that the appellant by his insurer the Commission, a professional and highly experienced litigant in the area of personal injury, made a considered commercial judgment to admit liability for negligence. That is, after conducting investigations it made a decision to admit liability, a decision in which it persisted notwithstanding it received legal advice in December 1999 that it should deny liability. It persisted with its admission notwithstanding legal advice that it had an arguable defence on liability. The question is what injustice or prejudice does the appellant suffer if he is now prevented from changing his position to plead an arguable defence to liability. The answer is no relevant prejudice. Contrast that with the position of the respondent. There is no evidence of specific prejudice such as the proven inability to trace witnesses as required in Gale. However, it is a serious matter to make an admission in a pleading, particularly an admission of liability, because from that point onwards the admitted facts cease to be in issue in the action and the parties proceed on that assumption: Sangora Holdings Pty Ltd v Dunstan, unreported; FCt SCt of WA; Library No 990172; 13 April 1999. In the period between November 1999 and June 2002 when the appellant foreshadowed his intention to make this application it can be inferred that the memories of witnesses would have faded and lines of inquiry may have become cold, consequences identified by the Full Court in Celestino at [14]. In other circumstances these matters, and other relevant considerations such as delay, cost and case management principles, may not outweigh relevant prejudice to the applicant to amend. They do in this case.