Both appealing to restore faith in both the party and politics at large, Ms Philips put forward her case in a slick video posted to Twitter, while Ms Nandy set out her argument in a letter to her local newspaper.
The third and fourth candidates to put their names forward now join Corbyn-era frontbenchers Clive Lewis and Emily Thornberry in the battle to take on the leadership following the worst election defeat for the party since 1935.
Ms Phillips, an outspoken critic of Mr Corbyn who joined the Commons five years ago, said the party should elect “a different kind of leader” and needed to recognise that politics had changed in a “fundamental way as she set out to challenge Boris Johnson “with passion, heart and precision”.
The Birmingham MP made no mention of policy in her opening campaign message, which instead focused on how she would lead the party, and her personal characteristics.
“I travelled around the country during the general election and what I was hearing from our amazing activists was that people don’t trust us any more,” she said.
“And that’s what I was hearing from voters. They don’t think we are honest and they don’t trust us to be the people who get to make the decisions.”
A YouGov poll of Labour members showed Ms Phillips polling in third place behind Keir Starmer and Rebecca Long-Bailey in the upcoming contest, with 12 per cent of first preference votes.
Meanwhile Ms Nandy held the support of just 6 per cent support in the same poll.
Having repeatedly made the case that the Labour party should regain the support of towns the length and breadth of Britain in the run up to her announcement, the MP wrote in a letter to the Wigan post: “I understand that we have one chance to win back the trust of people in Wigan, Workington and Wrexham.
“Without what were once our Labour heartlands we will never win power in Westminster and help to build the country we know we can be.
“I have heard you loud and clear when you said to earn that trust means we need a leader who is proud to be from those communities, has skin in the game, and is prepare to go out, listen and bring Labour home to you”.
She went on to lay out her mission to regain the so-called ‘red wall’ of constituencies in the north that had once been Labour’s heartland, but flipped to the Conservatives under Boris Johnson.
Other candidates in the race are expected to formally declare next week, with a new leader expected to be selected by the end of March.