Toby Melville/Reuters The mayor of London, Sadiq Khan, is pushing for a second Brexit referendum.

Alarmed by the possibility of a bad or “no-deal” Brexit, London Mayor Sadiq Khan has called for a second referendum on the contentious subject of the U.K.’s departure from the European Union.

In a Sunday Op-Ed published in The Observer, Khan said the British public has the right to “take back control” of the issue after U.K. Prime Minister Theresa May’s “abject failure” to negotiate a good Brexit deal for the country.

“I’ve become increasingly alarmed as the chaotic approach to the negotiations has become mired in confusion and deadlock, leading us down a path that could be hugely damaging,” Khan wrote.

“The British public should have a say on the outcome of the negotiations” - London Mayor @SadiqKhan calls for second #Brexit vote https://t.co/EB7t1ttrZq #Marr pic.twitter.com/t7KtAS9w8M — BBC Politics (@BBCPolitics) September 16, 2018

Britain is to due to leave the European Union at the end of March, but Khan warned the country currently faces two “incredibly risky” options ― both of which could have devastating impacts on the economy and people’s living standards.

“The unfortunate reality is that Theresa May has failed to negotiate a Brexit position with her own party ― let alone agree a deal with the EU,” Khan wrote. “With time rapidly running out, we are left with two possibilities ― a bad deal, which could end up being so vague that we leave the EU blind to what our future relationship will be, or a ‘no-deal’ Brexit.”

“Both these scenarios are a million miles from what was promised during the referendum campaign, only further exposing the lies and mistruths sold to the public,” Khan continued.

A “no-deal” would mean that Britain would exit the EU without a transition period. That would raise a host of questions about trade relations, the Northern Ireland border and the rights and privileges for the millions of citizens of EU nations residing in the UK and vice versa ― UK citizens living in EU countries.

May, who has faced mounting criticism at home over her handling of the Brexit negotiations, has repeatedly pushed back against suggestions of holding a second public vote on the issue.

“To ask the question all over again would be a gross betrayal of our democracy ― and a betrayal of that trust,” May wrote in the Sunday Telegraph earlier this month.

But Khan, a member of the opposition Labor Party, argued that May’s government has “looked unprepared and out of its depth” as it’s negotiated with the EU, “resulting in a litany of wrong turns.”

As such, the public “must get a final say” on the issue, Khan insisted. “This means a public vote on any deal or a vote on a no-deal, alongside the option of staying in the EU.”

“It’s time to take this crucial issue out of the hands of the politicians and return it to the people so that they can take back control,” the mayor said.