Jeremy Corbyn has defended his pledge to stay “neutral” in the event of a second Brexit referendum after his position was criticised as indecisive.

The Labour leader revealed during a Question Time leaders’ special on Friday that he would not back either side, putting him at odds with senior party figures including John McDonnell, Keir Starmer and Emily Thornberry, who have all said they would back remain.

His decision to take a “neutral stance” on a proposed referendum for a newly negotiated Brexit deal if Labour forms a government drew scorn from critics.

Corbyn’s disclosure – the first time he had clarified his position – came after significant pressure in recent weeks, with Boris Johnson repeatedly pressing him on the issue during their head-to-head debate on Tuesday.

During a campaign stop in Sheffield on Saturday, Corbyn – a longstanding Eurosceptic as a backbench MP – claimed that his stance represented a sign of “strength and maturity”.

Speaking to supporters outside an Amazon warehouse in the city, where he was launching the party’s plans to take on “bad bosses” and “tax dodgers”, he said: “I think being an honest broker and listening to everyone is actually a sign of strength and a sign of maturity.

Q&A Do I need ID to vote in the 2019 general election? Show Hide There have been trials of voter ID in local elections and the Conservatives have stated that they want to bring in some form of UK-wide ID requirement for voting in the future, but for this election there is no change to the current system. You do not need to show ID to vote in England, Scotland and Wales in a general election. You don’t even need to bring your polling card. You just need to tell polling staff your name and address. They will then cross your name off the list and give you a ballot paper. If you’re voting in Northern Ireland, you must show photo ID. Only the following forms of ID will be accepted at polling stations in Northern Ireland: A UK, Irish or EEA driving licence (photographic part) (provisional accepted).

A UK or Irish passport.

An Electoral Identity Card.

A Translink Senior SmartPass.

A Translink 60+ SmartPass.

A Translink War Disabled SmartPass.

A Translink Blind Person’s SmartPass. Your photographic identification does not need to be current, so even if it is out of date you can still use it to vote. The presiding officer will have the final say over whether or not the photograph matches that of the person intending to vote. Find out more about voting in Northern Ireland. Martin Belam

“My role as the Labour prime minister would be to ensure that [a second referendum] is carried out in a fair way, that the offers put are fair, and that I will carry out the result of that referendum.

“I think this is actually a sensible way forward that actually can bring people together.”

However, the health secretary, Matt Hancock, earlier attacked Corbyn, arguing that his position “won’t wash” with the electorate. He told Sky News’s Sophy Ridge On Saturday programme: “He has actively decided to be indecisive on the biggest issue of the day. It won’t wash with voters.

“I think it is an absolute disaster. You can’t ask this country to be its prime minister while not having a view on the biggest issue of the day.”

The Liberal Democrat leader, Jo Swinson – who is campaigning on a platform to revoke Brexit – also rounded on Corbyn, saying: “To me that is a total absence of leadership. Remainers in this country need a leader, not a bystander.”

The Labour party’s plan is to negotiate a new withdrawal agreement with the EU if it wins next month’s election, and then have a second referendum with remain on the ballot paper. In a Guardian article in September, Corbyn indicated that he would stay neutral.