1.5 to 2.2 mm. 

Unless identified by a recognised expert, the specimen should be examined with a microscope and photos showing details of genitals should be provided. In the comments box, state the key or ID method used and describe the size and identifying characters.

A common spider of agricultural fields and grassland. Partly subterranean, living between cracks in the soil. However, it may on occasion, be found higher up in vegetation, for example on shrubs.

Adults of both sexes found throughout the year. 

Widespread in central and south-eastern England but more scattered elsewhere.

Widespread but under reported. 

http://srs.britishspiders.org.uk/portal.php/p/Summary/s/Porrhomma+microphthalmum