The Unite head's comments suggest the shadow health secretary could win his support in a future leadership contest.
It is farcical that the employment regulations that MPs put into law are not accessible to their own staff.
The union is prepared to reduce the shortfall but will expect policy concessions in return.
The Labour leader’s changes have left his party best placed to overcome the crisis of political participation.
After today's comfortable victory, far greater political and financial challenges lie ahead for the party.
The trade unions accounted for 77 per cent (£2.4m) of all donations to the party, with just £354,692 received in individual donations.
Labour figures believe the party fears the evidence against Unite is embarrassingly thin.
The Unite general secretary signalled that he would no longer tolerate those who "welcome our money but don't want our policy input".
A survey by Lord Ashcroft shows 12% of the trade union's 1.42 million members would affiliate themselves to Labour under the new system but also that they oppose large donations to the party.
With Labour more reliant on large one-off donations from unions, the Unite general secretary is in a stronger position to push for policy changes.