In his first interview since losing his seat in the Commons, Ed Balls said on Friday that he was minded to give up politics for good following his surprise defeat in the general election.

The former shadow chancellor, who lost his Morley and Outwood seat to the Conservatives by 422 votes, revealed one misgiving about Labour’s campaign – that it should have been more pro-business – but otherwise avoided recriminations and instead accepted his share of blame for the result.

He also refused to attempt a full explanation for what went wrong for Labour, saying it was too early for him to have an answer.

I want to make a difference to the world outside of politics ... I’m not going to be dashing back Ed Balls

There has been speculation that Balls, who has been a powerhouse at the top of Labour politics since he started working for Gordon Brown in 1994, could seek an early return to the Commons through a byelection, but Balls told the BBC he was not planning a return to parliament and that “outside of politics is where I am going next”.

He went on: “You never say never about anything, because who knows what’s going to happen, but the reality for me now is that I want to make a difference to the world outside of politics. That’s how I’m thinking about things. I’m not going to be dashing back.

“I’ve been thinking about and writing about economics for 20 years and there’s really big issues out there … is the financial system sound, the development challenge which is pushing migrants into Europe. These are things where, for the first time, there’s real time to stand back and think and write a bit. That’s what I’ll do.”

Asked about Labour’s campaign, Balls said: “I think I wanted to be more pro-business but I also backed Ed Miliband 100%.”

Balls also accepted that his own unpopularity could have been a factor in the defeat.

“Ed Miliband said straight after the election he took responsibility but all of us have to bear our share of responsibility. Ed was the leader, I backed him as shadow chancellor 100%. In the end he didn’t persuade people he could be the prime minister, but I didn’t persuade people I could be the chancellor, either.”

With Labour leadership contenders now all, to varying degrees, saying it would have been better for the party to admit that Labour should have been running a surplus before the crash, Balls conceded this would have made a “small difference”.

Asked to admit not that over-spending caused the crash but that spending less would have left Britain better placed to deal with it, he replied: “Before 2007, it is a matter of record that we had a low level of national debt because of the decisions we had made but also we had a small deficit.

“People will now say that that small deficit should have had a small surplus. The reality is that would have made a small difference, not a big difference.”

But that would not have stopped the crash happening, he added.