For a part 36 offer to be effective it must ?

for an offer to fall within Part 36 it has to be:

a genuine offer to settle (as opposed to a tactical offer made purely to attract Part 36 costs consequences),

made in accordance with the strict requirements of Part 36.

Explanation:

A Part 36 offer can be made at any time, including before the commencement of proceedings.3 However, although an early offer can provide substantial cost benefits and costs protection, a party may not be in a position to make an informed offer until proceedings have been commenced. If not made at the outset, Part 36 should be reconsidered throughout the case. Part 36 offers can also be made in appeal proceedings4 and in relation to claims for costs in detailed assessment proceedings.

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