It is a two-storey house, made of gritstone and granite flush quoins, with a dalabole slate roof and twelve paned windows with Georgian glazed panels, five of them at the front.

[4] The central entrance hall on the north-east front leads to a large oak staircase, and the library (refurbished in late 19th -early 20th century) and main drawing room are located on the south-east side.

The drawing room has a central floral rose and a Carrara marble chimneypiece.

[5] In 2000 Tresillian was purchased by George Edward Silvanus Robinson (born 1956), who was a founding partner of the City of London hedge fund Sloane Robinson, founded in 1993, which in 2008 was the sixth biggest European hedge fund with assets under management of $15.1 billion, but in 2012 ranked 32nd with $3 billion in assets.

[7] He is a prominent donor to the Conservative Party[8] and in 2004 was appointed a trustee of the right-wing think-tank Policy Exchange.