The television deal for the Six Nations is expected to be announced on Thursday afternoon with the BBC having teamed up with ITV in a bid to keep the tournament on terrestrial television.
The RBS 6 Nations is on the BBC until 2017 but cuts to the broadcaster's budget had led to speculation it would be outbid by Sky.
An announcement is expected on Thursday afternoon and sources with knowledge of the negotiations have confirmed the BBC and ITV have been working on a combined bid for the 15 games a year for a fee of around £50million. The broadcasters would share the live matches and highlights equally.
Labour's shadow sports minister Clive Efford welcomed the joint bid saying it would be a "huge mistake" for the tournament to be limited to pay TV which would in effect mean the absence of all top-level rugby union from terrestrial television.
Efford told Press Association Sport: "I have made inquiries and I understand this is a serious bid from the BBC and ITV and one to be welcomed.
"It's healthy for sports to have some of their elite events on terrestrial TV and rugby needs to have access to a platform that is accessible to everyone if it wants to grow and inspire the next generation.
"I think if the Six Nations followed the elite club competitions and England's autumn internationals onto pay TV there would be a backlash and pressure would be put on politicians to put it on the A List of sporting events."
The BBC's current deal is believed to be worth £40million a year.
The Rugby Football Union sees value in the sport having a higher profile on terrestrial TV while Sky subscribers benefit via the autumn internationals.
Some Celtic unions, especially Scotland, are understood to be more open to seeing the tournament on Sky or BT Sport if it means more income for them.
The deadline for tenders was last week and expectations that Sky - which showed the last British Lions tour - would win the rights outright did not materialise. ITV's interest in rugby is at a peak with its exclusive coverage of this autumn's Rugby World Cup.
Efford claimed the government's cuts to the BBC meant it was inevitable it would struggle to secure sports rights.
He said: "The threat of these huge cuts is that things we have seen on BBC may come to an end as they don't have the commercial possibility to increase revenue. That's a serious problem and could have dire consequences.
"It is therefore a sensible move by terrestrial TV stations to work together."