Ed Miliband hit back at critics of his leadership on Friday, insisting he had a "very clear plan" but that restoring public confidence in Labour would take time and that he relished the fight.
In an interview with The Guardian at the end of a tough week for the Opposition, Miliband rubbished suggestions of splits within the shadow cabinet over the need to accept some spending cuts.
And he struck a combative note over executive pay ahead of announcements expected this weekend by David Cameron on the issue - saying voters would never believe the Prime Minister wanted a "more responsible capitalism".
"These are the hard yards of opposition. We have taken the hard road, not the line of least resistance," Miliband said when confronted with criticisms of his 15-month tenure.
Labour peer Lord Glasman, the architect of the Blue Labour philosophy who has advised the leader in the past, complained this week that the party appeared to have "no strategy, no narrative and little energy".
Under Miliband, the opposition "show no signs of winning, the economic argument", he added.
But Miliband defended his record as "the guy who took on Murdoch" over phone hacking and called for a shake-up of capitalism to remove "predatory" firms.
"I always knew it was going to be a fight. It is one I relish - I never expected it to be anything else," he said.
"What is the most important thing for a leader of the opposition to have? It is to establish an argument about what is wrong with the country and what needs to change.
"I have a very clear plan and I have set out very clear themes."
The Conservatives seized on remarks by shadow defence secretary Jim Murphy that Labour needed to show "credibility" by explaining where it would make cuts as signs of dissent against the leadership.
But Miliband said in fact Murphy's announcement that he would accept £5 billion-worth of the government's military cuts was "exactly what (shadow chancellor) Ed Balls said he wanted shadow ministers to do.
"There are lots of cuts we are not going to be able to reverse. That is the way it is. To say otherwise would not be credible," he said.
Winning back public faith in Labour's ability to handle the economy would take time though, he cautioned.
"It is an incredibly important task, not something that takes place in six months or a year. We - Ed and I - get this more than anyone, that this is an important task for Labour."
The prime minister has signalled that he will unveil further measures to curb bankers' bonuses this weekend, saying the level of City remuneration was "completely out of whack".
Miliband challenged him to match Labour's pledges on the issue.
"If one of the big battlegrounds of British politics is going to be who is really going to take action on executive pay, I say 'bring it on'. I promise you they are not going to steal a march on us in this area.
"Does anyone really believe that David Cameron came into politics to create a more responsible capitalism? The public are not going to buy it.
"My test for him on executive pay is whether he would do what Labour would do if we were in office now: put an employee representative on every remuneration committee, make firms publish their pay ratios, empower pension companies and investors, and have another year of the bank bonus tax to get some of our young people back to work.
"There can't be any more foot-dragging and backsliding. If David Cameron wants a more responsible capitalism - responsibility at the top and the bottom - then this would be a start."