Tory and Labour peers have reached a deal ending the deadlock which threatened to block a 5 May referendum on changing the Westminster voting system, Lords leader Lord Strathclyde has said.
On 31 January 2011, as peers debated the Parliamentary Voting System and Constituencies Bill at committee stage for the fifteenth day, Lord Strathclyde revealed that a "package of concessions" on the bill had been promised to the opposition.
He predicted that the marathon committee stage debate on the bill would conclude on Wednesday.
But Labour's Lord Falconer of Thoroton signalled that further concessions may be necessary if the bill is to be returned to the Commons on February 14 for MPs to consider amendments made in the Lords.
The Electoral Commission has warned the the bill must become law by mid-February to allow time for the referendum to be prepared for May.
After committee stage the bill must also be considered by peers at report and third reading stages.
The government accepted in principle an amendment tabled by the convenor of crossbench peers, Baroness D'Souza, which reinstates public inquiries in the boundary review process in certain circumstances.
The crossbench peers' amendment would allow, but not compel, the Boundary Commission to hold a local inquiry where an objection raised "substantive issues". Inquiries would take no more than six months.
Advocate General Lord Wallace of Tankerness told peers: "The government proposes a public hearing process enabling the opportunity for the public and for the parties to express their view."
The Liberal Democrat peer said this would allow for "sensible discussion" of proposed boundary changes, while still allowing a cut in the number of MPs from 650 to 600 to take place in time for a 2015 general election.
Lady D'Souza withdrew her amendment, telling peers she was encouraged by the minister's response to her arguments.
She added that crossbench peers had been motivated to intervene in the "impasse" by "the shadow or the threat of anything approaching a 'closure motion' in this House".
There have been suggestions that the government was preparing to introduce a new procedural rule for this bill, enabling peers to curtail debate on a piece of legislation for the first time.
Such a "guillotine" procedure, Lady D'Souza warned, would "undoubtedly impair the role that we play in revising and scrutinising legislation".