When Underhill (1923-77) died 40 years ago, his wife closed the studio and refused all requests from visitors, including representatives sent by Tate director Nicholas Serota.
Now his children have control of the estate the studio has been opened, revealing what Sworders describes as an “untouched time capsule”.
The studio contained paintings, an easel, brushes and a collection of photographs featuring works made by Underhill and how the artist worked in his studio.
The collection, containing 15 lots with estimates ranging from £200-800, is being offered at Sworders’ Modern British and 20th century art sale at its Stansted Mountfitchet saleroom today.
Underhill was one of the Australian School artists who came to London after the Second World War. He exhibited in galleries including Annely Juda and the Whitechapel Art Gallery and his talent was noted by art critics Robert Hughes and Bryan Robertson. His work is in public collections such as Art Gallery of New South Wales and the National Gallery of Victoria.