Very common bright orange lichen, but can be quite green when saturated or in shade. The abundant apothecia are orange with a lighter margin. Found on exposed coastal rocks but also on other substrates

References: 
Smith, C.W. et al. editors (2009) The Lichens of Great Britain and Irelandd
Dobson, F.S. (2018) Lichens: an Illustrated Guide to the British and Irish Species