A man speaks to people during a march against the outcome of the recent EU referendum, in London, Britain, July 2, 2016.(Xinhua)

LONDON, Aug. 24 (Xinhua) -- Owen Smith, the member of parliament (MP) challenging Jeremy Corbyn for the leadership of Britain's Labour Party, said Wednesday he would demand a second EU referendum to allow the population to vote on a Brexit deal.

Smith, one of the shadow ministers who quit Corbyn's front bench team in the House of Commons, vowed to try to stop Conservative Prime Minister Theresa May from triggering the Brexit process unless she agrees to a new referendum on the final deal, or as an alternative signals a general election.

Corbyn, estranged from most of his MPs in parliament, but enjoying massive grassroots support, has responded by saying Labour, currently the official opposition party in parliament, should work with the result of the June 23 vote. By 52 percent to 48 percent, the British population voted to quit the European Union after a membership spanning more than four decades.

May has said she would not trigger Article 50 during 2016 and faces demands from some of her own MPs to start the process as quickly as possible. Firing the starting gun on article 50 would start an irreversible process to arrange a legal exit from the EU within a set time frame of no more than two years.

In an interview Wednesday, Smith said the British people were "lied to" by Leave campaigners, commenting: "It would be irresponsible of Theresa May to simply trigger Article 50 and sleepwalk out (of the EU). Labour still believes that we should be a part of the European Union."

Smith said he would "fight tooth and nail" to keep Britain in the EU, adding that under his leadership of the party, Labour would oppose the triggering of Article 50 in a future Commons vote unless certain conditions were met.

He insisted: "We will vote in parliament to block any attempt to invoke Article 50 until Theresa May commits to a second referendum or a general election on whatever EU exit deal emerges at the end of the process."

Currently it is not known whether the 650 members of the British House of Commons will be given the opportunity to vote on triggering article 50. A challenge in the British law courts is currently deciding whether Parliament should have a say before Article 50 is triggered.

May's government insists the process can start without the need for a vote of all MPs in the House of Commons.

Labour Leave campaigners later described Smith's pledge as "electoral suicide."

On the leadership campaign trail Corbyn said as leader of the Labour Party will be fight for public ownership of the country's National Health Service (NHS), saying privatization and outsourcing of services are draining the NHS of resources that could be used to improve patient care.

Addressing an audience at University College Hospital in London, Corbyn said: "Privatization and outsourcing don't just erode the founding principles of the NHS, they're actually a terrible waste of resources."

The British media though refused to let go of a story that has earned the nickname, "traingate." Corbyn's campaign team issued a video showing the Labour leader sitting on the floor of a Virgin rail train between London and the North East. He commented that the train was crammed full of passengers and he was unable to find empty seats for him and his wife. Eventually seats were found.

But the rail operator released photographs taken from on board closed circuit cameras, which Virgin claimed showed there were vacant seats on the train.

Corbyn has announced the re-nationalization of railways in Britain if he becomes prime minister. Virgin, headed by billionaire entrepreneur Sir Richard Branson, would be one of the losers if his policy is introduced.

At Wednesday's meeting to discuss his policy on the NHS, Corbyn was angered when he faced more media questions about the rail story. He insisted he was "there to talk about the NHS."

Britain's watchdog on data protection, the Information Commissioner's Office, said Wednesday it is "making inquiries into the publication of CCTV images of Corbyn on the train."

There have been complaints the release of the images has broken data protection rules.