Amber Rudd was failed by her officials during the row over immigration policy which led to her resignation as home secretary.
The ex-home secretary quit the Cabinet after she "inadvertently misled" the Home Affairs Select Committee over targets for the removal of illegal immigrants.
But a report into the row found officials repeatedly gave her wrong information and then failed to clear up the problem.
Ms Rudd said: "There are elements of this report which just show that, unfortunately, that area of the department did not have a grip on what was going on.
"I hope that there will be changes made as a result of this report so that people get a better service from Immigration Enforcement."
On BBC Radio 4’s Today programme, she questioned why the report had been "sat on for nearly six months".
"There were a series of leaks during the past year at quite a high level that were definitely intended to embarrass me," she said.
The report could clear the way for Theresa May to promote the Hastings and Rye MP back into the Cabinet - Ms Rudd said it was now "up to the Prime Minister" whether she returns to the front bench.
The document, obtained by the Times, reveals she asked officials for advice on targets before her ill-fated appearance at the Home Affairs Committee in April at the height of the scandal over the treatment of the Windrush generation.
The report, written by Sir Alex Allan, the Prime Minister’s adviser on ministerial standards, says "crossed wires" contributed to Ms Rudd’s downfall.
She "was not supported as she should have been" by her officials before, during and after the committee appearance on April 25.
"In preparations immediately before the hearing, the home secretary asked 'Are there removals targets?' and was told 'No'. This led to her denial in the hearing," writes Sir Alex in an executive summary.
He adds: "I cannot establish how she was given this reply: the most likely explanation is crossed wires between her special adviser and her private office."
Ms Rudd told the Commons Home Affairs Committee the Home Office did not have targets for removals.
The following day, however, she returned to the House to admit Immigration Enforcement managers did use "local targets".
A note later emerged referring to a target for enforced returns and progress towards a 10% increase "which we promised the Home Secretary earlier this year".
Sir Alex wrote, following the then home secretary’s answers at the committee there were "confused email exchanges trying to establish the position on targets".
"The home secretary (was) never provided with a briefing that might have allowed (her) to put the correct position on the record," the report said.
The report singles out for criticism the "less than satisfactory performance" of then director-general for immigration enforcement Hugh Ind, who has since moved to a different role in Whitehall.