A Labour party rebel who defied leader Ed Miliband to vote against unemployment reforms did so upon principle, he has claimed.

Ian Mearns had to quit his post on the bottom rung of the ministerial ladder for failing to toe the party line by not abstaining from a vote on a government bill.

Instead, he voted against retrospective legislation tabled by the coalition in a frantic response to a ruling by a judge on welfare benefits for jobseekers.

Labour's frontbench team wanted to offer no resistance to the bill, after securing concessions that would allow jobseekers to appeal against rulings on their benefits claims.

But Mearns told IBTimes UK that he had to defy the Labour leadership over the vote. He spoke after standing down from his role as parliamentary private secretary (PPS) to Ivan Lewis, the shadow secretary for international development.

The MP for Gateshead said: "Based on my casework experience I do not have any real faith at all that [work and pensions secretary] Iain Duncan Smith could oversee a fair, open and transparent mechanism at the DWP. We were voting for possible sanctions on everyone since 2011. That's not fair.

"Then I had to resign, or it would have been a case of getting the sack because I had voted against the wishes of the leadership of the party on this issue."

Labour thrashed out its position on the bill at a meeting which left many MPs uncomfortable.

"The line being taken by the frontbench team was one that everyone was not comfortable with," said Mearns. "I have talked to colleagues and many of them who abstained did so with a very heavy heart."

Worries that resistance to the workfare bill would be a gift to the Tories influenced the controversial decision.

Mearns said: "The timing [of the vote] was unfortunate. On the day of the Budget, the [shadow] frontbench did not want to run the risk of being called irresponsible.

"But there's neither a good nor a bad time when we want to do the right thing."

A total of 43 Labour MPs rebelled against the party whip in a show of defiance that would have been uncomfortable for Miliband. But the Labour rebels' stance slipped under the radar with George Osborne's Budget dominating the news agenda.

Mearns insisted that the Labour rebels were not drawn only from the "awkward squad" of the party's MPs.

"There was a broad range of people, they are not the loony left," he said.

Among those who also defied the party leadership was Labour's former chief whip Nick Brown and former housing minister John Healy.

The bill was triggered by a court ruling in February that found that jobseekers were not given enough information about how to appeal against cuts in their benefits.