A £7.5m competition to create England’s next national forest has just been launched – and the green space might end up being the size of Greater London.

The new woodland is expected to cover between 200 and 600 square miles in the Midlands or North of England, with millions of trees to be planted in the coming decades.

This means the forest would cover an area the size of Birmingham at its smallest, and could be as large as the entirety of Greater London.

It is the latest step in Labour’s manifesto commitment to create three new national forests in England.

The first, the Western Forest, is already under way and will stretch across Bristol, Wiltshire, Gloucestershire and Somerset, with more than 20 million trees to be planted by 2050. A competition for the second, in the Oxford-Cambridge Growth Corridor, has recently concluded.