Wingspan 7 to 9 mm. The larval feeding  causes a rounded mine on the upper surface of leaves of Hornbeam; the mine has a white papery surface.  Mature mines may cause the leaf to contract.

Similar mines are formed on Hazel by P coryli

Adult Leafmine

Photograph mine and note host species in comments

Areas where Hornbeam is present.

The adults emerge, like many other Phyllonorycters, in May and again in August as a second brood.

The larvae feed on Hornbeam (Carpinus betulus) 

A local species, mainly found in the south and south-east of England northwards to the midlands. In the Butterfly Conservation's Microlepidoptera Report 2011 this species was classified as local.

Increasingly well recorded in Leicestershire and Rutland in recent years, particularly from the leafmines on Hornbeam.

http://www.leafmines.co.uk/html/Lepidoptera/P.esperella.htm

https://bladmineerders.nl/parasites/animalia/arthropoda/insecta/lepidoptera/ditrysia/gracillarioidea/gracillariidae/lithocolletinae/phyllonorycter/phyllonorycter-esperella/