The assistant chief executive of Camden Council has resigned after five and a half years.

Sarah Mullen announced her departure in an email to colleagues last week.

She said: “I am writing to tell you that I will be leaving Camden in the middle of July.

“After five and a half fantastic years, I have decided that it is time for a change in direction. Needless to say, it will be a big wrench for me to leave Camden behind.”

She added: “In the meantime there is a lot to be delivered between now and the summer, and so it will be full steam ahead until I go.

“I am fully committed to supporting the transition to a new administration and leading our busy work programme, not least the extensive work associated with the financial strategy and planning for the implementation of a new HR service in the autumn; as well as keeping our business as usual services on the road.”

Ms Mullen originally joined the council on a 12-month secondment from the Treasury before moving into a permanent role.

Recruitment for her replacement is not expected to begin until after local elections on May 22.

The council’s interim head of communications, Peter Holt, also left his role last month by mutual agreement after being appointed to cover communications director Kathryn Myers while she was on maternity leave.

Mr Holt’s appointment provoked criticism from the Liberal Democrat opposition as he had served as Labour leader of Merton Council before quitting politics in 2000.

A council spokesman said: “He had done a good job since joining us and assisted the council in successfully campaigning against the government’s HS1/HS2 link – he left with our thanks.”