Unite general secretary Len McCluskey has said the union is delighted to have been "vindicated" over the Falkirk Labour candidate selection row and that it was time to "move on".
Speaking to BBC1's Andrew Marr Show, he said Labour leader Ed Miliband's reforms were not about "cutting" the union link but about creating a new relationship for the 21st century.
"We want to engage in a proper debate and a discussion to see whether we can strengthen the relationship and make certain that we create a Labour Party that is on the side of ordinary working people.
But Mr McCluskey warned Ed Miliband needed to demonstrate to both the unions and the working population that Labour was "on their side".
""The challenge really for Ed is to make certain now that he demonstrates to ordinary working people, and indeed to organised Labour, that the Labour Party is on their side.
"We certainly support that and we are going to be working enthusiastically to see if we can bring that about", he added.
More top news
Temperatures have already plunged to -12C in some parts of the UK this winter - but Thursday could be the coldest day yet.
The 86-year-old has been removed from his position as CEO of Formula One as US giant Liberty Media completed its £6 billion takeover.
Donald Trump's press secretary has said the Trump administration's "intention is never to lie to you", amid a row about inauguration crowds.