The Labour party will place a spending cap on selection campaigns, Harriet Harman announced today.
Speaking on BBC1's Andrew Marr Show, Harman said the move was part of a "significant change" in the party's relations with trade unions, following Labour's row with Unite over allegations of ballot rigging.
The Shadow Culture, Media and Sport Secretary said she had taken out a second mortgage on her home to fund her campaign to be deputy leader, because she was not backed by a union.
It is very important that people cannot be ruled out of a contest because they can't get the backing of a union or have their own independent funds.
Labour leader Ed Miliband has turned on the trade union Unite - his biggest financial backer - whose votes helped him become leader.
Tom Watson has announced his resignation from the shadow cabinet, amid a row about the influence of the union Unite on the Labour party.