A bashful Chuka Umunna dismissed suggestions he may be promoted amid a looming shadow cabinet reshuffle.
The shadow business secretary told Daybreak he "loved" his job and felt "extremely privileged to be an MP".
The Labour MP for Streatham said he hoped to become the Business Secretary if Labour were elected in 2015.
The Government is selling Royal Mail short by "pressing ahead" with its current sale, despite selling it at a "huge undervalue", the shadow business secretary said.
Chuka Umunna told Daybreak Royal Mail was valued at "between £2.6-3.3 bn" and endorsed by City brokers.
He warned the sale was becoming "a dream" for City speculators but a nightmare for the taxpayer.
Labour's shadow business secretary Chuka Umunna told the BBC's Newsnight that claims the policy could see the lights go out was "patently absurd" and "nonsense".
Labour's shadow business secretary Chuka Umunna said the Government was selling off the Royal Mail to make amends for George Osborne's "failed plan":
Ministers are pushing ahead with this politically motivated fire sale of Royal Mail to fill the hole left by George Osborne’s failed plan.
This is taking place despite opposition from a huge coalition including the Conservative Bow Group, the Countryside Alliance, the National Federation of Subpostmasters, the cross party BIS Select Committee as well as Royal Mail employees themselves.
The Government has not addressed the huge concerns which remain on the impact the Royal Mail sale will have on consumers, businesses and communities, but ministers are ploughing on regardless.
Shadow business secretary Chuka Umunna has rejected suggestions a cut in union funding would mean financial meltdown for Labour.
Speaking to the BBC Radio 4 Today programme, he said: "For us as parties, we've fundamentally got to change the way we operate if we are to make our parties relevant in the 21st century.
"Part of that involves making sure we've got a better connection with our communities and our people. I think the trade union link gives us a huge head-start over other parties in that respect, because it gives us a direct link to three million working people.
"What we are seeking to do is to ensure that we've got a better link to individual members."
Mr Umunna added: "Undoubtedly, we are going to take a hit in terms of our finances, but that doesn't mean that it isn't the right thing to do."
Shadow business secretary Chuka Umunna said if the Prime Minister "changes his position and comes back to Parliament seeking Parliament's sanction for military action, then as a responsible opposition then of course we would have to consider that but the same criteria would apply".
Chuka Umunna, Labour's shadow business secretary, has said the government has some "very serious questions to answer" over why it approved export licences of chemicals to be sent to Syria in January 2012.
"In light of the fact the Assad regime had already been violently oppressing internal dissent for many months by the beginning of 2012 and the intelligence now indicates use of chemical weapons on multiple occasions, a full explanation is needed," he added.
Speaking on the BBC's Newsnight programme, shadow business secretary Chuka Umunna defended the Labour leader.
Polls go up and down - what actually matters are votes. I know that under Ed Miliband's leadership, the Labour Party has put on an extra 2,000 councillors, importantly in marginal areas where we need to win back seats at the next General Election.
It's votes and members that actually matters. All of this relates to living standards. Ed started talking about the squeezed middle at the start of his leadership and everybody ridiculed him. This is the biggest issue facing our country now.
There is a "danger" controversial zero-hours contracts, which do not guarantee the employee any hours of paid work, become "the norm", said Shadow Business Secretary, Chuka Umunna.
New evidence highlights that there could be hundreds of thousands more people on zero-hours contracts than previously thought...Flexibility works for some, but the danger today is that too often insecurity at work becomes the norm.
The huge spike in the use of zero-hours contracts has brought increased reports of abuses and bad practice. There should be zero tolerance of such abuse.
That is why Labour has convened this important summit bringing together representatives of employers and employers to consider what action must be taken.
Labour MP Chuka Umunna, the Shadow Business Secretary, has tweeted his disapproval of employment tribunal fees:
Bemused at silly Tory comments on opposition to ET fees - those who lose most from their attack on employee rights are non t/union members!