Sources say decision to collect ‘modern’ art could have two galleries ‘at each others’ throats’ – but others welcome move

A decision to tear up an agreement between the National Gallery and Tate, which has prevented the National Gallery from collecting works created after 1900, could create “bad blood” and a situation in which the two galleries are “at each other’s throats”, according to senior sources.

The National Gallery announced the shift as part of Project Domani, whereby the 200-year-old institution will receive £375m of investment for a new wing that will usher in a “new tomorrow”.

Maria Balshaw, the director of Tate, officially welcomed the announcement, saying it was planning to work closely with the National Gallery to “further the national collection as a whole”. A working group featuring staff from both galleries has also been established.

But the Guardian understands that behind the scenes, the decision to change the collection policy at the National Gallery is seen by some as a threat to Tate and a shift that could revive an old rivalry.