Sir, The suggestion that the so called cartin is an eco-friendly alternative to a tin is misleading ('The incredible shrinking Christmas confectionery', 3 September).

The introductory trial of the cartin was, as its name reflects, just that: and at the time, the only reference made to its eco-credentials was to it being lighter. The pack was snubbed by consumers who preferred the traditional version a real tin and the trial concluded.

Using metal, a material that should never go to landfill and is truly recycled in an infinite loop while retaining its original resources, may well be regarded as opting for the real eco-friendly option.

Jumping to conclusions in this very complex area only exacerbates misunderstandings over what constitutes 'eco-friendly'.

Nick Mullen, director, Metal Packaging Manufacturers Association