The service has been asked to reduce its overall budget by 20 per cent (£500m) by 2015.
As a consequence, the comms department's budget will be cut by about a third and its workforce reduced from 150 to 100.
About 35 of those exiting the department are taking voluntary redundancy and will leave by mid-June.
The other 15 roles have disappeared as a result of people leaving the organisation and not being replaced.
Apart from new director of media and comms Martin Fewell, who joined in September, the Metropolitan Police has not been recruiting comms staff over the past 12 months.
The remaining staff will be reorganised into a central department under Fewell's control, although some will continue to be based in individual boroughs. Currently, about half of the staff are based in specific units and not managed by Fewell.
'Various different policing directorates or other divisions within the Met may have quite a lot of their own comms resources at the moment,' said Fewell. 'We're bringing it under one management, so that we can do it more efficiently and deliver a clearer and more consistent message.'
The comms department will continue to have four divisions: news, including a 24/7 press bureau and social media; internal and change comms; marketing and publicity, which handles marketing campaigns and public information; and external relations.
The Metropolitan Police is also on the hunt for a new internal comms head to help oversee engagement with staff over the wider organisational changes.
Last year, the organisation introduced a major staff engagement programme. As part of the Total Professionalism initiative, Fewell and other senior managers, including commissioner Bernard Hogan-Howe, have attended a series of meetings with more than 10,000 staff to get feedback on the change programme and culture.