The ballot in the Labour leadership contest is to open as party members decide who will be Jeremy Corbyn’s successor.
Members and party supporters who have signed up for a fee will begin receiving their ballots on Monday, with batches being sent out by email and post throughout the week.
They will decide between Keir Starmer, Rebecca Long-Bailey and Lisa Nandy as to who will take on Boris Johnson at the despatch box.
They will also select a new deputy leader between candidates Angela Rayner, Dawn Butler, Ian Murray, Dr Rosena Allin-Khan and Richard Burgon.
Sir Keir, the shadow Brexit secretary seen as a clear frontrunner, said in a Durham hustings that he would offer senior roles to both of his opponents if he won.
“I would happily offer both these candidates a top job in the shadow cabinet and I’d happily serve them if they wanted me to do the same,” he said.
Rebecca Long-Bailey, the shadow business secretary who has struggled in the polls since being seen as an early favourite, said she would accept a job in either of their shadow cabinets and offer them both roles.
“I would, I think they’re both brilliant,” the shadow business secretary said. “And I would do whatever I was asked and whatever it takes to make sure, if I didn’t become leader, to make sure we were elected as the next Labour government.”
Wigan MP Nandy also praised her opponents in confirming she would give them key roles.
“I like both of these people, I respect them. I would want them in my shadow cabinet doing big jobs,” she said. “But I would equally be happy to serve alongside them in whatever role they chose to give me.”
The candidates have nearly six weeks to secure voters’ support before the ballot closes but many were expected to make their voices heard at the first opportunity.
The winners are set to be named on April 4 before taking up the roles immediately.