Britain's prime minister is scrambling to avoid another defeat on her Brexit strategy amid opposition from members of her own party who fear she is moving in the wrong direction in efforts to overcome the impasse blocking a deal.

Hardline pro-Brexit lawmakers say a measure to be voted on Thursday rules out the threat of leaving the European Union without an agreement on future relations, undermining Britain's bargaining position. Prime Minister Theresa May has previously ruled out a "no-deal" Brexit as she attempts to win concessions from the EU after Parliament rejected her deal last month.

European Council President Donald Tusk has reiterated his frustration with Britain, tweeting "No news is not always good news. EU27 still waiting for concrete, realistic proposals from London on how to break #Brexit impasse."