When the court makes an order about costs, it may carry out a summary assessment then and there and order the payment of a sum of money in respect of costs, or it may order a detailed assessment of the costs. If a detailed assessment is ordered the receiving party must, amongst other things, prepare a bill setting out the work done and, ultimately, the court will go through that bill, hearing argument from both sides as to what items and amounts should and should not be allowed.

The general rule is that the court will make a summary assessment of the costs at the conclusion of the trial of a case which has been dealt with on the fast track and at the conclusion of any other hearing which has lasted for not more than one day. In certain cases, the Court of Appeal will also carry out a summary assessment. Summary assessment will be carried out unless there is good reason for not doing so, for example where the paying party shows substantial grounds for disputing the sum claimed for costs that cannot be dealt with summarily, or there is insufficient time to carry out a summary assessment (CPR 44.6; Part 44 Practice Direction (paras 8 and 9)).