Newly-elected Labour leader Jeremy Corbyn has begun the task of putting together a unifying shadow cabinet by announcing that Rosie Winterton will keep the crucial chief whip role.
The veteran left-winger is drawing up a new-look front bench after his seismic victory in the leadership race sparked a flurry of senior resignations among more centrist MPs.
"We are a movement and a party renewed," he said.
"After the overwhelming mandate we achieved today, we are bringing together a new parliamentary team to take our message to the country.
"We go forward united and determined, and I am delighted to have appointed Rosie Winterton to continue to serve as Chief Whip. Rosie has served our party under consecutive administrations and will be a valuable part of our new team."
Ms Winterton, a former aide to John Prescott and a minister under Tony Blair and Gordon Brown, held the chief whip role - in charge of enforcing party discipline - throughout Ed Miliband's leadership.
The scale of Mr Corbyn's victory - taking almost 60% of the votes and topping the ballot among party members as well as registered supporters and trade unionists - has all-but quashed talk of disgruntled moderates seeking to oust him.
In his acceptance speech he called repeatedly for "unity" and announced his ambition to lead a Labour "fightback" after demolishing the challenge of mainstream rivals Andy Burnham, Yvette Cooper and Liz Kendall.
But the scale of his task in bringing the party together around a radical programme was underlined by the immediate departure of several frontbenchers.
Ms Cooper was joined by Rachel Reeves, Emma Reynolds and Jamie Reed in announcing they would not serve on the frontbench while Ms Kendall, Tristram Hunt and Chris Leslie had already indicated their political differences with Mr Corbyn.
Ed Miliband - whose resignation after leading the party to general election disaster in May provoked the contest - called on the party to join him in supporting Mr Corbyn but indicated that he too would not seek a return to the frontline.
However, shadow business secretary Chuka Umunna - a senior centrist who withdrew from the contest after a matter of days - issued a plea for the party to "come together" behind its new leader "and focus on providing the most credible and effective opposition to the Tories".
Corbyn supporters chanted "Jez we did" and sang the socialist anthem The Red Flag as they celebrated his comprehensive victory, taking 59.5% of the vote - 251,417 of the 422,664 votes cast - against 19% for Mr Burnham, 17% for Ms Cooper and 4.5% for Ms Kendall.
Downing Street said David Cameron - who has warned Labour under Mr Corbyn posed a threat to the UK's security and economic health - had telephoned his new adversary to congratulate him.
The pair are due to face off for the first time at Commons question time on Wednesday.
Ms Winterton faces some tough challenges managing a party riven by a sometimes bitter leadership contest between wings of the party.
An early test may be any vote on extending UK military action against Islamic State into Syria, something opposed by the new leader but which has support among many MPs.
Shadow culture secretary Chris Bryant welcomed Ms Winterton's reappointment.
"Few know how to win votes in the Commons like her," he wrote on Twitter.