Other offices, including London, will be opened as restrictions ease.
In response to staff feedback calling for increased flexibility, The Openwork Partnership has said staff will be trusted to choose where, when and how they work around their personal and professional commitments.
Colleagues should be available for core hours between 10am and 2pm, but can fit work around other commitments once agreed with teams and managers.
Employees will be able to work all or part of the time in the office or work from home with visits to the office for meetings or for collaboration with colleagues.
Staff – including the 100-plus who have joined during the COVID-19 pandemic and have never worked in the office – are supported with a specially designed Flexible Working Portal site which has guides and videos on new working practices and options.
Carrie Morris, chief people officer at The Openwork Partnership, said: “It is an exciting new chapter for the company and there will be major benefits for colleagues in terms of motivation, recruiting and retaining colleagues as well as in the work-life balance and productivity.
“Colleagues told us in surveys that they wanted more flexibility and we recognised that the world has changed and that the way we work needs to change too.
“Flexible working aims to provide everybody with the work-life balance choices that enable each of us to reach our full potential professionally and personally.
“As we emerge from the COVID era some will be keen to stop working from home while others will be worried about returning to the office – importantly, no one will be expected to work in the office unless they are comfortable in doing so.
“We may all feel different after a few months of normal life so we may need to flex and adapt as time goes by.”