A rare and beautiful wildflower is being reintroduced to the countryside by Kew Gardens and the plant charity Plantlife after it was mistaken for a weed and killed off by farmers and gardeners.

The red hemp-nettle was once common in southern England and South Wales but the use of herbicides, fertilisers and the spread of highly productive crop varieties have led to it almost vanishing from fields.

The plant is pretty, delicate purplish-red flowers poking up from short green leaves.

Now, it can only be seen in a few dozen parts of the country, and keen horticulturalists often go on day trips to try and catch a glimpse of the little flowers.

The nettle is now being replanted in the countryside as conservationists fight its extinction.

To help the scheme, some 27,000 seeds of the wildflower have been sent from Kew Gardens' Millennium Seed Bank to the Royal Agricultural University (RAU), where they have been sown in experimental plots to find the best conditions for reintroducing them.

The experiment at the university's Harnhill Farm, near Cirencester, will look at the germination and survival of the red hemp-nettle under three different conditions, in plots without crops and others sown at normal or reduced rates.