The battle to take control of promoting professional snooker has taken another twist with Altium Sports withdrawing their guarantee of a world-ranking circuit of at least nine events for the next five years.

This circuit is promoted by the WPBSA, who sought an investor when it became clear that it could promote only six world-ranking events in the coming season as opposed to nine in the last campaign.

Altium, backed by the City finance house Warburg Pincus, guaranteed an initial £2.5m investment whereas its rivals, World Snooker Enterprises, were offering no new investment.

Critics of the WSE bid have questioned how they intended to promote nine events with no new investment given that the WBPSA had made it obvious that it could promote only six.

John Davison, who headed the Altium bid, said: "Altium was disappointed to withdraw its offer of investment in the commercial future of snooker. We spent eight months developing this proposal.

"However, Altium became increasingly uncomfortable with the process adopted and managed by the WPBSA board and considered the descriptions of its offer made by the board to its members to be incomplete and potentially misleading."

Players were to have been invited, at a meeting today, to express a preference between the rival deals. A June 28 players' meeting, which produced a tied vote, saw the world champion Peter Ebdon suggest the decision was far too important to make without knowing further details and also urged that the matter go to an independent auditor, but Deloitte & Touche maintained that they could not audit the future.

The WPBSA has also declined to provide players with any assessment of the abilities of Altium or WSE to fulfil the terms of their proposals, insisting that this matter need only be addressed at contract stage after the vote.

The WPBSA insists that it has dealt with the rival proposals with scrupulous impartiality.