Marks & Spencer has unveiled a Plan A-inspired fashion capsule collection for its Indigo range.

The 15-piece collection, called Indigo Green, uses fair-trade and organic cotton and is designed to offer “fashion with a conscience”. It will be sold in stores and online from April.

Marks & Spencer head of design for womenswear Neil Hendy said Indigo Green’s prices are similar to those of the wider Indigo range and run from £15 to £45.

Indigo Green reflects current fashion trends such as 1970s looks, including tie-dye, batik and maxi-dresses. There is also a variety of denim items.

Director of Plan A Richard Gillies said: “It really begins to show how we are taking sustainability into the mainstream of the business.”

The retailer’s Plan A sustainability programme has so far benefited M&S’s bottom line by £50m.