This type of activity is currently covered by the Betting Gaming & Lotteries Act 1963.
Pool betting involves pooling the stakes of the participants, deducting a proportion of the stakes to cover expenses, tax and operators profits, and, when the result is known, sharing the remainder of the “prize pool” among the winners. The level of individual prizes depends on the number of winners and cannot be predicted with any accuracy in advance.
The Registration under the 1963 Act is subject to the fee of £464.