Marks & Spencer has come under fire from campaigners over a £2 surcharge on bras sized DD and above.

The Busts 4 Justice campaign group said the pricing discriminated against bigger busted women and that other items of clothing such as T-shirts and trousers were priced the same.

One campaigner has bought one share in the company so she can confront boss Sir Stuart Rose about the issue at the Marks & Spencer AGM in July.

The retailer said bigger bras needed more work to develop a greater level of support in the garment and therefore the extra cost was justified. M&S told The Daily Telegraph that it had ruled out changing its bra prices. A spokesman said: “We have looked at it but will not be making any announcements on this.”

The campaigners have set up a Facebook account to persuade people to lobby M&S and it has attracted more than 7,800 members.

Meanwhile, rival Asda has said this morning that it doesn’t penalise bigger busted women. It invests £4m per year into charging a flat rate for all bras, from cup sizes A through to F.

Fiona Lambert, George’s brand director said: “Retailers should put an end once and for all to one of the last prejudices - that of the bigger busted woman.  Real women come in all shapes and sizes and so bras at George are exactly the same price from A cup through to F cup.”