UPDATE: 13:25 BST
Leave backing Labour MP Kate Hoey has now entered the race to challenge Benn. Her supporters include former First Minister of Scotland Alex Salmond.
Senior Labour MP and Remain campaigner Hilary Benn is set to become the chair of a new House of Commons committee scrutinising the government's Brexit plans. Nominations for the chair of Exiting the European Union group close today (18 October), with a vote held tomorrow.
MPs have decided the chair of the committee will be from Labour. But Benn, the former shadow foreign secretary, is the only candidate in the race.
The 62-year-old clashed with Jeremy Corbyn during his time serving on Labour's front bench.
The rivalry came to a head after the EU referendum when Benn told the left-winger he had no confidence in his leadership.
Corbyn subsequently sacked the Labour heavyweight, triggering a string of resignations from the leader's top team and 172 Labour MPs backing a vote of "no confidence" against Corbyn.
But Corbyn's re-election as leader saw the Islington North MP secure a bigger mandate, while self-styled "moderate" Labour MPs have sought to maintain and boost their profiles through parliament's committee system.
Benn, meanwhile, has attracted heavyweight indorsements. Former Labour leader Ed Miliband has thrown his support behind Benn as well as Greater Manchester Mayor candidate Andy Burnham. Former Conservative ministers Anna Soubry and Andrew Mitchell have also backed Benn.
Benn, the Leeds Central MP, has promised to "respect" the UK's decision to leave the EU. "I campaigned for Remain, but I believe we must respect the British people's decision, implement it and get the best possible deal for the United Kingdom," he said.
"There are a large number of substantive issues that the committee and the House will need to deal with as part of this process now that the government has indicated when it will trigger Article 50 (the mechanism to split from the EU).
"These will include the government's negotiating plan, ensuring continued access to European markets for all our industries and services, future arrangements for immigration control from the EU and maintaining cooperation with our European neighbours in areas like foreign."
The government is currently facing a challenge in England's High Court over its authority to trigger Article 50 without a parliamentary vote. Theresa May has promised to make the move by March 2017.