LONDON, Sept 7 (Reuters) - The Bank of England on Tuesday said it would no longer require staff to come back to the office at least once a week from September, citing health concerns among of some of its employees. British Prime Minister Boris Johnson has reopened England"s economy, but decisions by employers over whether - and how quickly - to mandate the return of workers to offices could have a big impact on the pace of recovery from the COVID-19 slump. Britain is reporting around 40,000 new cases each day, a figure that could rise as the return of pupils to school after the summer break contributes to the spread of coronavirus. In July, the BoE"s Chief Operating Officer Joanna Place said that every employee would be asked to work in the office at least one day per week from September. But the Bank of England on Tuesday said that, while there was an "expectation" that staff would be "physically present in the workplace at least one day a week and generally more" from next week, it would now no longer be mandatory. "What has changed is that we don"t feel the moment is yet right for us to require our staff to return to the office where, for a number of reasons, some might in the current environment have genuine and valid health concerns about doing so," the Bank of England said in a statement. "This will be kept under close review with a view to making the expectation a requirement as the situation evolves." The BoE said a quarter of its London staff were in the office at least one day last week, while adding that offices in some other parts of the country were at pre-pandemic occupancy levels already.