The Blackpool South MP announced the local amount on Thursday after the Government confirmed a national package of more than £41 million for 74 heritage projects across England.
The official programme identifies the Blackpool building as a first-phase project intended to create a new cultural and creative use. Webb said he had lobbied for support for the town.
The grant is part of a wider heritage regeneration drive rather than a separate £1 million fund created for Blackpool. Delivery responsibility and the detailed scope of the first phase will sit with the project partners.
Bringing the former Post Office back into use could add activity to the town centre and create space for community and creative organisations. The award does not by itself complete the conversion.
Webb's intervention connects a national heritage programme to a prominent local building, while avoiding the stronger claim that an MP alone secured a departmental funding decision.
The next tests will be the project timetable, matched funding where required and the uses that occupy the building once the initial work is complete.
