The UK government has nominated former cabinet minister Liam Fox as its candidate to lead the World Trade Organization.
The body is searching for a new director-general to replace Brazilian Roberto Azevedo at the end of August.
Boris Johnson said Mr Fox was a "passionate advocate of multilateralism" with "detailed knowledge" of global trading.
Labour said the WTO would "immediately discount" Mr Fox for the role.
Shadow international trade secretary Emily Thornberry said it was "extraordinary" Mr Johnson would choose a candidate he fired from his role after becoming PM, adding: "There will be little trust in somebody who promised so much in regards to Britain's future trade yet delivered so little."
Mr Fox, a Conservative MP since 1992, was an ardent backer of the UK's exit from the EU.
He said he was "honoured" to be nominated, adding: "I believe that if we want to keep the WTO relevant and vibrant our task is clear: Update, strengthen and reform.
"We must ensure that global trade works for everyone."
Seven candidates from other countries have also been nominated for the role.
His nomination by Downing Street will come as a blow to former Labour cabinet minister Lord Mandelson, who has also expressed an interest in the role.
WTO member countries have until 17.00 BST on Wednesday to nominate candidates, with voting set to begin later this year.
WTO head quits early as global downturn looms
WTO chief: 'Months' needed to fix disputes body
Brexit: What is the 'no deal' WTO option?
The contest comes at a crucial time for the WTO, amid a slump in global trade in the wake of the coronavirus pandemic.
The Geneva-based body, established in 1995, provides a forum for its 164 members to administer a system of rules governing global trade.
Recently however the body has seen one of its main functions, arbitrating trade disputes, hobbled by a dispute with the United States.
President Donald Trump's administration has blocked the appointment of new judges, arguing that the WTO has long treated the US unfairly.
Despite being a Brexiteer who wants to see the UK embrace what he sees as the opportunity of signing new trade deals from next year, Liam Fox was sacked immediately by Boris Johnson when he became PM.
But it now seems the PM thinks Mr Fox could be the man to fight for his vision of global free trade.
Mr Fox's supporters have spoken of the need for a "political leader" at the WTO - and point to his connections with many influential Republicans in Washington.
He's not the frontrunner. Many countries are expecting an African leader of the organisation - with the favourite from Nigeria at the moment.
Mr Fox joins a field of candidates including Kenya's culture minister Amina Mohamed, who became the latest to confirm her candidacy on Tuesday evening.
They join Egypt's Hamid Mamdouh, Tudor Ulianovschi from Moldova, and South Korea's Yoo Myung-hee.
Jesús Seade Kuri from Mexico and Ngozi Okonjo-Iweala from Nigeria complete the field.
The UK is currently aiming to negotiate a free trade agreement with the European Union following its exit from the 27-member bloc in January.
The UK government has ruled out an extension of the deadline to reach a deal, which will come when a 11-month transition period ends in December.
If the two sides fail to reach a bespoke agreement, trade between them will default to the standard international set of rules set by the WTO.