It would divide art historians, many of whom argue that British art should be seen in the context of work being done abroad.
That was the criticism levelled at Timothy Clifford, director of the National Galleries of Scotland, when he proposed a separate Edinburgh gallery for Scottish art three years ago. That has not yet got off the ground.
Dividing the Tate's British and international collections would be more daring because of their size and importance. However, the casual visitor has always been confused by the Tate's differing duties - Britain's principal museum of modern 20th century art and the main collection of British painting since the 16th century.
The Tate director Nicholas Serota's policy of rehanging the collection every two years may have delighted regular attenders; but to make room for neglected works, those by key artits can no longer be hung permanently and foreign visitors risk disappointment.
Stanley Spencer, who had a whole room in the 1990 rehang, does not now have a single picture on display. A coherent story of the development of British art cannot be told in the Tate, where only 500 of its 4,000 works can be displayed, and the rehang policy means those may not necessarily be the most important 500.
This summer the trustees considered development plans which involved utilising a former nurses home owned by the Tate on its Millbank site and possibly acquiring a neighbouring site used by the Ministry of Defence. The plans could cost well over pounds 50m.
Using those spaces would mean the Tate could increase its display area by two thirds, enabling a separation of the collections. The idea is likely to be discussed at the trustees' meeting next month. One source said splitting the collection was fast proving the favourite option.
A spokeswoman for Mr Serota, who is on holiday, said: 'The gallery has to assess the needs of the next 20 years. A number of options are being considered and separating the British and modern is certainly one, but there will be no announcement until the autumn at the earliest.'
Mr Serota is understood to think that, if there is a split, the history of British art should remain in the existing building.Reuse content