Wales is poised to see its first double parliamentary and Welsh assembly by-election after the death of Independent MP and AM Peter Law.
Peter Law overturned the largest Labour majority in Wales
It is likely the Westminster and assembly elections for Blaenau Gwent will take place on the same day.
Mr Law, who died on Tuesday, was expelled by Labour after standing successfully as an Independent MP in protest at all-women shortlists.
Leading Commons tributes Tony Blair said Mr Law was a "conscientious" MP.
Labour will be particularly keen to win his assembly seat to regain a working majority in Cardiff Bay.
Mr Law had been suffering from a brain tumour first diagnosed during the 2005 general election campaign.
He had been Blaenau Gwent's Labour AM since the assembly was set up in 1999, but fell out with his party over its decision to select a parliamentary candidate from a woman-only list.
Mr Law stood as an Independent and turned Labour's 19,000 majority in its safest Welsh seat into a 9,000 majority of his own.
He was automatically expelled from Labour as a result, becoming an Independent AM.
Peter Law continued to travel to Westminster despite his illness
But that meant Labour lost its overall majority in the 60-seat assembly, which has meant it has had to rule as a minority administration for the past year.
There are claims that Labour whips at Westminster have attempted to use pressure to urge an early by-election in Blaenau Gwent.
BBC Wales understands that assembly Presiding Officer Dafydd Elis-Thomas has rejected an approach as insensitive.
He was said to be refusing to consider an election date before Mr Law's funeral at Christ Church, Ebbw Vale.
That would mean that the assembly election at least would not be held before 22 June - although, in theory, the Westminster contest could be held on an earlier date.
Senior Labour sources declined to comment on a matter which they said had to be handled sensitively.
There is a precedent for a post-devolution double by-election: they were held in the Westminster and Scottish Parliament seat of Glasgow Anniesland in 2000 after the death of First Minister Donald Dewar.
The three opposition parties in the assembly have confirmed they will field candidates, dismissing speculation they might not stand to improve the chances of an Independent candidate.
Labour has already selected John Hopkins to stand in the 2007 assembly election and he is expected to be the assembly candidate in the by-election.
Labour has yet to select its candidate for the parliamentary seat.
Dai Davies, who was Mr Law's agent, has confirmed he will stand for one of the by-elections.
He said he will be advised whether or not he should run for the assembly or parliament by members of Blaenau Gwent People's Voice group.
Plaid Cymru said it expected local activist John Price to stand in the assembly election and possibly a "prominent party figure" in the Westminster contest.
Neither the Conservatives nor Lib Dems have yet made any selections for either seats.
In the House of Commons on Wednesday, Mr Blair spoke of his "sadness" at the death of Mr Law.
"He was a conscientious MP and won the respect of all who knew him for the courageous way he fought his illness," he said.
"Our thoughts are with his family at this time."