Xysticus ulmi

The broad cross line across its abdomen is characteristic.

A sexually dimorphic species, with the male being much darker than the female. It is very similar to X. cristatus though usually has a more elongated abdomen. The epigyne and male palpal organs are the distinctive features.

Confirmation requires microscopic examination of the genitalia of adult specimens. 

Identification of this species  "Requires examination at high magnification in good lighting, typically examination of the genitalia." Bee, L., Oxford, G., & Smith, H. (2020). Britain's Spiders: A Field Guide. Second Edition. Princeton University Press.

This crab spider prefers damp habitats.

Seen mainly in spring and early summer.

Does not build a web but lies in wait for prey.

Quite common and widespread in most of England and Wales, but less frequent further north.

Fairly common in Leicestershire and Rutland.

1421 British records to Jan 2013