Global investing maven Mark Mobius had unforgiving words for the U.K.'s leadership ahead of crucial Brexit votes this week.
Speaking to CNBC at the Global Financial Forum in Dubai, the asset management mogul said it was Prime Minister Theresa May's time to depart.
"I think May has got to go," Mobius, founder of emerging markets fund Mobius Capital Partners, said Monday. "I think she doesn't have the leadership capability. You've got to have somebody who is going to be willing to say what she thinks, personally, and lead and say 'Look, I don't believe in Brexit, and we should change."
"I definitely think she's against Brexit — she was in the beginning. I'm sure now it's even more."
Indeed, the embattled prime minister quietly supported remaining in the European Union before the June 2016 Brexit vote, warning of adverse effects to the U.K.'s economy, security and even its union with Scotland. Since becoming head of government, however, she has pledged to "honor the results of the referendum," reiterating that "Brexit means Brexit."
The U.K. is scheduled to leave the EU on March 29.
"It's a mess. Why doesn't she come out and say 'I'm against this, I think it's a bad idea, these are the reasons, this is how it's going to affect us?'" Mobius asked, adding that he expected the pound to weaken after this week's crucial parliament vote. Some experts say the pound could drop as much as 25 percent against the dollar in the event of a no-deal Brexit.
May has survived near-mutinies after members of her Conservative Party and later opposition party lawmakers held separate votes of no-confidence in her leadership, but she suffered a crushing defeat of her painstakingly negotiated Brexit deal with EU leaders in January.
On Tuesday, lawmakers will vote for a second time on May's Brexit deal. If a simple majority doesn't approve the deal, lawmakers will then vote on whether Britain should leave the 28-member bloc without a deal.
A no-deal Brexit would be catastrophic for the U.K. economy and spill over to international markets, a wide consensus of economists and business leaders have warned.
If parliament members vote against a "no-deal" Brexit, they'll then have a vote on whether to extend Article 50 (which sets out the departure process) and delay Britain's March 29 departure.
Experts are divided over the likely outcome of Tuesday's vote, with a large proportion of those surveyed by CNBC predicting another resounding defeat for May and a subsequent delay of Brexit by two to three months.
May and other Brexit officials have made several trips to Brussels to try to get concessions from EU leaders in the deal to allay the concerns of U.K. lawmakers, who are primarily focused on the Irish "backstop." The backstop is a mechanism to avoid restoration of the "hard" border between Ireland and Northern Ireland that was erased with the 1998 Good Friday peace agreement between London and Dublin. It was designed to ensure that should Britain and the EU fail to resolve their future trading arrangements, there can be no possibility of a physical border being erected within the island of Ireland.
The EU has kept a firm stand, offering only reassurances that the backstop is seen by European officials as a last resort.
On Sunday, British Foreign Minister Jeremy Hunt said that Brexit could be reversed if lawmakers reject the government's exit deal. This came after two major euroskeptic factions in parliament warned that May faced an overwhelming defeat.
Mobius is one of the vast array of investors and market moguls criticizing the U.K.'s vote to leave the EU and its politicians' subsequent leadership.
Speaking to CNBC in February, BlackRock chief executive Larry Fink slammed what he called the "irresponsibility" of the U.K.'s leaders, saying that "Brexit is an immediate problem, and it's a problem that's quite frankly annoying every private sector organization in the world today."
—Reuters and CNBC's Holly Ellyatt contributed to this article.