“31. The important misunderstanding that has occurred is that, if (i) there is a non-trivial (now serious or significant) breach and (ii) there is no good reason for the breach, the application for relief from sanctions will automatically fail. That is not so and is not what the court said in the Mitchell case: see para 37. Rule 3.9(1) requires that, in every case, the court will consider “all the circumstances of the case, so as to enable it to deal justly with the application”
“35. The “extreme course” to which [Lord Justice Jackson] was referring was that non-compliance would no longer be tolerated, save in “exceptional circumstances”