From August masks must be worn inside church buildings.
From the Church of England website (https://www.churchofengland.org/more/media-centre/coronavirus-covid-19-guidance-churches#na):
In England, face coverings are currently required by law to be worn in shops, supermarkets, indoor transport hubs, indoor shopping centres, banks, building societies, post offices and on public transport.
From 8 August, face coverings are also required by law to be worn in a greater number of public indoor settings including places of worship, museums, galleries, cinemas and public libraries.
There are valid exemptions for some individuals and groups not to wear a face covering in these settings. In particular, those who are leading services or events in a place of worship, and those who assist them (for instance by reading, preaching, or leading prayer) do not always need to wear a face covering, although one should be worn especially if physical distancing cannot be maintained (i.e. distributing consumables). This exemption does not apply to worshippers, who should wear face coverings consistent with the requirements for any other public space.