JEREMY Corbyn has hinted that Labour frontbenchers, who defy his order to support the passage of the UK Government’s Brexit Bill, might go unpunished, stressing how he was a “very lenient” leader.

His remarks came as his colleague John McDonnell, the Shadow Chancellor, predicted that once Brexit was no longer the all-dominant subject on the political agenda and other issues came to the fore, then Labour during the next 12 months would move ahead of the Conservatives in the opinion polls. The Tories currently have a 12-point lead.

Mr Corbyn has been struggling to contain a revolt by pro-Remain MPs opposed to his decision to support Theresa May’s EU Notification of Withdrawal Bill, which authorises ministers to trigger Article 50 and which marks the start of the formal two-year divorce process.

Read more: Theresa May rules out Scots deal on immigration despite warnings

Last week, Jo Stevens and Rachell Maskell, the respective Shadow Welsh and Environment Secretaries, resigned from the Shadow Cabinet, as did Dawn Butler, the Shadow Minister for Equalities, over the leader’s three-line whip to support the bill; Labour’s official position is not to frustrate its passage through Parliament.

There was anger among some Labour MPs that Diane Abbott, the Shadow Home Secretary, and a close ally of Mr Corbyn, escaped without punishment when she missed last week's Second Reading vote on the Bill, claiming a migraine attack, despite the three-line whip.

The Labour leader, struggling to fill holes in his frontbench team, is now facing the prospect of an even larger rebellion when the bill receives its final vote at Third Reading on Wednesday with Clive Lewis, the Shadow Business Secretary - seen by some as a future leader - reported to be among those who could vote against.

Read more: Theresa May rules out Scots deal on immigration despite warnings

Asked whether frontbenchers who defied party orders could keep their jobs, Mr Corbyn told BBC Radio 4's The World This Weekend: "You are asking me a very hypothetical question here. I will be making an announcement during the week." But he then added: "I am a very lenient person."

The London MP – who as a backbencher famously rebelled more than 500 times against the leadership - has yet to decide what to do about ten junior shadow ministers and three party whips, who also took part in last week’s rebellion in which a total of 47 Labour MPs defied their leader.

Meantime, Emily Thornberry, the Shadow Foreign Secretary, insisted that whatever happened to Labour’s proposed amendments to the bill, the party would not seek to block the legislation at the key Third Reading vote.

"There are many ways in which the Government may be able to react to this that will be positive," she explained.

"There will need to be back channels, private conversations. There are many conversations going on now. We are speaking to Government, we are speaking to Tory backbenchers and we are trying to get a compromise that will work," she added.

Elsewhere, Mr McDonnell forecast Labour would overturn the Conservatives’ double-digit poll lead within the next 12 months.

Read more: Theresa May rules out Scots deal on immigration despite warnings

The London MP told BBC Radio’s Pienaar’s Politics that Labour, prior to Mr Corbyn being elected leader, was 12 to 14 points behind in the polls but within a year was just behind or level with the Tories.

“Then we had the coup and the leadership elections; in the last 18 months, we spent half of them in leadership elections. People won’t vote for a divided party, we know that, and that’s why we’re behind in the polls.”

Mr McDonnell argued once the Article 50 legislation had passed Labour would have the chance to rally behind other issues.

He added: “Once we get past Brexit we’ll unite the Labour party, we’ll be back on our agenda and you’ll see that we’ll have a significant impact upon the political debate in this country, which will mean that we’ll go back in front of the Tories in the polls over the next year.”