She said she hopped the current leadership contenders would “engage in an open and honest debate about the tough challenges we face.
“If they fail to do so, they will be doing the party a disservice.”
She said the manifesto Labour created fell short of what was needed to convince the votes.
And was responsible for “more fear than hope in voters’ hearts and minds.”
She wrote: “Despite some individual good ideas, the confetti of policy bribes created an unbelievable and unaffordable agenda.
“I felt the manifesto was one of the most reactionary documents I had seen.
Its emphasis on a big state and on state ownership, a vilification of success and an obsession with the producers of public services, rather than the citizens for whom those services are for, together served to frighten rather than inspire the public. Recycling the policies of the 1970s proved neither radical nor transformative.”