Holy Trinity Heydon sits at the centre of the village. It is a Grade 2* listed late 15th century medieval church with an extensive 1865-6 east end by Joseph Clarke.
Following bomb damage in 1940, the building was restored by Sir Albert Richardson, who rebuilt the north nave and aisle in imitation of the remaining south side but built the short west tower in red brick. This is capped with copper, which with the copper gutters of the nave are a distinctive feature of the church.
Brown long-eared and pipistrelle bats live in the church and they access the church through the eaves. Roosts are located in the gaps of the roof timbers with possible maternity roosts and possible day roosts.
Bat droppings are found throughout the church, particularly affecting the alabaster reredos and brass altar furnishings