"Every church should have CCTV and someone stood on the door. Firstly, to welcome people; secondly, to act as a spotter if someone is approaching the church carrying a weapon," said Nick Tolson, chief of the UK's National Churches Trust who has drafted the guidance released this week.
"People looking to attack will often carry a weapon openly because they believe they are going to be killed anyway, so why hide them? The churches should also have doors that can be closed securely," he said.
Tolson is a former police officer and has advised the UK Home Office on counter-terrorism measures since 2012.
He has drafted the measures for National Churchwatch, which produces personal safety advice for people who work at places of worship.
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As well as advising religious leaders how to avoid being targeted, the measures give directions about what to do if an attack takes place.
It reads: "If someone produces weapons during a service (and this will usually be a knife or blunt instrument) then you will need to get people out of the church.
Last month, the UK government announced a 2.4 million pound fund to protect churches and other religious institutions from hate crimes.