Britain's Takeover Panel gave the Carlsberg and Heineken consortium until January 21, to make a formal takeover offer for Scottish & Newcastle Plc or withdraw.
The regulator issued its "put up or shut up" notice after the Danish-Dutch consortium first approached S&N in mid-October, and then last month put forward a proposal to pay 750 pence a share for S&N in cash, valuing the Edinburgh-based brewer at £7.3 billion.
S&N, the brewer of Foster's, Kronenbourg and Newcastle Brown Ale, had approached the panel to try and bring the two-month long bid situation to a head and avoid continued distractions to its trading performance.
S&N has rejected the bid approach, and has refused to meet the bidding consortium for takeover talks.
Both sides welcomed the introduction of a timetable. S&N said it would bring the long period of uncertainty to an end, while the Carlsberg team continued to urge S&N to open talks to agree the terms of a formal recommended offer.
The consortium's preference is to engage in friendly talks with S&N's management rather than go for a hostile bid as it wants to carry out due diligence before making its formal bid to break up the British brewer.