North Norfolk District Council has been accused of incompetence after Great Yarmouth Borough Council poached half its senior management team after a shared services agreement broke down.

Sheila Oxtoby is to become the new full-time chief executive of Great Yarmouth Borough Council, having filled the post part-time since November under an interim shared management arrangement with North Norfolk District Council.

She will be joined by North Norfolk chief finance officer Karen Sly and head of HR Julie Cooke, who also worked across both authorities during the trial.

Today's announcement follows the decision by North Norfolk's Cabinet last week to break the arrangement to share a senior management team with the neighbouring authority.

As well as the chief executive, the tie up also saw North Norfolk chief finance officer Karen Sly and head of HR Julie Cooke working for both NNDC and Great Yarmouth Borough Council.

Council leader Tom FitzPatrick told the meeting the time was not right to continue the arrangement on a permanent basis - a decision expected to be approved by full council on September 21.

A statement from Great Yarmouth Borough Council today read: 'Due to the timescales involved in recruiting a chief executive and the fact the interim arrangements can be ended by either party with one month's notice, Great Yarmouth's full council met last Thursday (September 8) to decide next steps.

'In recognition of her service to date, full council voted unanimously to offer the position on a full-time, permanent basis to Mrs Oxtoby, who this week accepted the offer. A start date is yet to be announced.

'Councillors also agreed to offer full-time permanent positions at Great Yarmouth to two other shared staff – Karen Sly, the section 151 officer, and Julie Cooke, the head of human resources – who have accepted the respective offers.'

The North Norfolk Labour Party has accused North Norfolk District Council of incompetence and urged leader, Tom FitzPatrick, to resign.

Stephen Burke, chair of North Norfolk Labour Party, said: 'Losing one senior officer is careless, losing half of the senior management team is completely incompetent. This story follows the bad press over councillors awarding themselves 23% pay rises while making cuts to local services, and a number of councillors being in arrears for a number of years over council tax. The ruling Conservative group has left our district council in chaos.

'The loss of our local council's most senior staff raises massive questions about the costs and impact of the sharing arrangement with Great Yarmouth. These are questions which Cllr FitzPatrick as Leader of the Council must answer. Why have they resigned? What will councillors do to ensure proper leadership at the top of the council? What has been the cost to taxpayers in North Norfolk?

'Councillor FitzPatrick must very quickly get a grip on our local council or do the honourable thing and resign.'

Mrs Oxtoby said she was 'honoured' to be offered the position at Great Yarmouth.

'During the last 10 months, I have been impressed by the ambition and dedication of Great Yarmouth's councillors and officers to deliver for communities,' she said. 'There are many exciting opportunities ahead for the borough and I look forward to working on a full-time basis with councillors and officers to make the most of these for residents and businesses.'

Great Yarmouth said it moved quickly to recognised the exceptional work of the three officers during their time with them.

In a joint statement, Councillor Graham Plant, Councillor Kay Grey and Councillor Trevor Wainwright said: 'Councillors are clear that Great Yarmouth needs officers to fill these important strategic roles on a full-time basis, in order to lead in the delivery of the council's priorities at a challenging time for the public sector.

'During their 10 months at Great Yarmouth, these three officers have done exceptional jobs, working well with existing staff to support the ambitions of the council and the borough. Sheila, as chief executive, has proved both a genuine ambassador for Great Yarmouth and an experienced strategic thinker.

'Recognising this sterling service, full council agreed to offer the full-time positions to the incumbent officers, before committing to the extra time and costs associated with seeking staff externally. We look forward to continuing to work closely with these officers in future.'