[5] A study in 2012 found that it has spread from the Scottish Highlands north into Sutherland and Caithness and southeastwards from the Great Glen into Moray, Aberdeenshire, Perthshire, Tayside, and Stirlingshire, with some in the Central Belt, on the Kintyre and Cowal peninsulas and on Skye and Mull.

Analysis of a scat found at Kidland Forest in Northumberland in June 2010 may represent either a recolonisation from Scotland, or a relict population that has escaped notice previously.

[9] In July 2015, the first confirmed sighting of a European pine marten in England for over a century was recorded by an amateur photographer in the woodlands of Shropshire.

Scat found in Cwm Rheidol forest in 2007 was confirmed by DNA testing to be from a European pine marten.

All of the martens were fitted with radio collars and are being tracked daily to monitor their movements and find out where they have set up territories.

During autumn 2016, the VWT planned to capture and release another 20 European pine martens in the hope of creating a self-sustaining population.

[21] Following the success of these projects, 35 European pine martens were reintroduced between 2019 and 2021 to the Forest of Dean in South West England where they were last seen in 1860,[22][23] with the hope that in time they will merge with the growing population in Wales to form a contiguous presence.

[26] A study managed by academics at Queen's University Belfast, using cameras and citizen scientists, published in 2015, showed that European pine martens were distributed across all counties of Northern Ireland.

This enables them to lead more arboreal lifestyles, such as climbing or running on tree branches, although they are also relatively quick runners on the ground.

[5] The recovery of the European pine marten in Ireland has been credited with reducing the population of invasive grey squirrels.

The young are usually born in late March or early April after a month-long gestation period that happens after the implantation of the fertilized egg, in litters of one to five.

[6] Persecution (illegal poisoning and shooting), loss of habitat leading to fragmentation, and other human disturbances have caused a considerable decline in the European pine marten population.