I have only just noticed that hidden in the logo of each Toblerone bar of chocolate is the image of a bear. It’s strange, it’s not really hidden – it has always been there, I have just never spotted it until someone pointed it out to me.

In the same sense the obligation on a contractor to “constantly use his best endeavours to prevent delay in the progress of the Works or any Section” is hidden. The obligation to use best endeavours to prevent delay is wide ranging as it applies to any delay “however caused”.

The new 2016 JCT suite has left this provision untouched and therefore the bar remains high for a claiming contractor to clear before he can secure relief from liquidated damages and gain extra time to complete. What best endeavours actually requires, has along with all reasonable endeavours or just plain reasonable endeavours, been the subject of much judicial thought.

Arguably, best endeavours requires the contractor to take steps and actions irrespective of the financial or commercial impact, or to put it another way to prevent delay he must “leave no stone unturned” (Sheffield District Railway Co v Great Central Railway Co). However, in deciding whether a contractor has met this test you have to consider what his “best” is and examine his capacity, resources and the nature of the tasks required to prevent delay before deciding if best endeavours have been used.

I wonder how many contractors pursuing an extension of time claim, or for that matter employers challenging that entitlement, really test whether best endeavours have been used to prevent delay. In many cases like the Toblerone bear, that key requirement may be hidden.