Council chiefs could offer perks like subsidised housing and extra-long holidays in a bid to attract new social workers to Birmingham's beleaguered children's services department.

The proposal comes as the true extent of the council's difficulties in hiring and keeping children's social workers can be revealed for the first time.

Failings by social workers and other child protection staff were highlighted in a series of serious case reviews into the death of children, including Birmingham youngsters Keanu Williams and Khyra Ishaq.

The department, rated inadequate for the past five years, was branded a "national disgrace" by the Government's chief inspector of schools last October.

And new figures have revealed that over a quarter (27 per cent) of its 610 full-time social worker posts are currently vacant – 12 per cent higher than the level deemed "safe" by Ofsted.

And a report, put to the council's vulnerable children scrutiny committee, has revealed that 18 per cent of the department's social workers are agency staff – with some earning up to £30,000 more a year than permanent staff.

A three-year action plan to boost the hiring and retention of children's social workers by 2017 has now been unveiled – including a £400,000 spend on advertising in 2015 alone, as well as a social media recruitment campaign.

The report details plans to recruit staff from overseas, with perks for workers brought in from outside of the West Midlands including extended holidays, subsidised housing and annual £3,000 bonuses to spend on training.

The plan, which would also see a graduate recruitment drive at UK universities, would also aim to cap agency rates of pay and "significantly reduce" the number of temporary workers.

The report reads: "Agency workers are valued as a flexible resource with which to address deficiencies in capacity or to respond to fluctuations in demand. Birmingham recognises that an over-reliance on this group of workers has had a negative impact on the morale of permanent staff."

Currently there are 7,000 children in Birmingham "in need" – including 1,900 in care and over 1,000 under a child protection plan.

But the report outlines a bleak picture of the council's ability to staff the child protection team – with social workers leaving in their droves.

While 292 new staff have started since January last year, more than that number left in the same period, says the report.

"The number of leavers is now greater than the number of new starters, creating a deficit which will further impact upon service delivery," reads the report.

"It's no surprise that Birmingham is struggling to attract and retain experienced staff.

"And whilst there is no simple solution, employers need to examine every aspect of the recruitment and employee journey and make as many incremental enhancements as possible to improve recruitment and retention.

"A positive and proactive response to this challenge is hindered by Birmingham's poor record for retaining children's social workers, resulting in a workforce that does not ever reach stability."

The report said that while nationally the average children's social worker remains in the same post for eight years, in Birmingham it is no longer than five years.

And in Birmingham, the team has suffered a 42 per cent turnover in leadership – blamed on a cull of staff in 2012, when "a whole cohort" of team leaders were made redundant.

The report warned it would "take time" to deliver a "stable and high performing workforce".

"Without the workforce being in place, the aim of receiving a ‘good' Ofsted rating within three years will not be possible," it added.