Image copyright M&S

Marks and Spencer is paring back its fruit and veg labelling to be more environmentally friendly, replacing stickers with laser-markings.

From Thursday, M&S will sell avocados bearing what look like pale tattoos, showing a best-before date and origin.

Peeling away the traditional labelling will save 10 tonnes of paper and five tonnes of glue a year, says M&S.

More of its fruit and vegetables may be laser-branded in future, the retailer says.

"The laser just takes off one layer of skin and instead of inking it or burning it, the skin retracts and leaves a mark," says Charlie Curtis, senior produce agronomist at Marks and Spencer.

"What we're putting onto the fruit is country of origin, best before date and there's a short code so you can put it through quickly at the [checkout] till."

Media playback is unsupported on your device Media caption Charlie Curtis from M&S showed the BBC's Science in Action programme how lasering works

While the printed sticker is an effective way to label most groceries, they are sometimes prone to coming unstuck, particularly when applied to very dry, wrinkly or shiny surfaces. Alongside avocados, sweet potatoes and coconuts are among the more challenging products for the supermarket sticker-gun.

It's taken M&S six months to perfect the laser process for avocados, but if the trial rolling out this week goes well they expect laser-labelling to be extended to more products.

Avocado and custard

Previous experiments with citrus fruits proved disappointing, since the laser penetrated too far into the very soft, porous skin and made the fruit deteriorate faster. But Miss Curtis says they have high hopes for many other fruits and vegetables, possibly including lasering pumpkins with "cut here" scarey faces for Halloween.

M&S has also experimented with lasering a complete barcode onto the avocado, but the skin was too uneven. However, it may work for other products, Miss Curtis said.

Image copyright Thinkstock Image caption Avocados have become a very fashionable ingredient in recent years

M&S said the avocado was first introduced in its UK stores in 1968 as an "avocado pear" and some customers consumed it "as a dessert with custard".

These days its more likely to be served "smashed" on toast, as guacamole or even in a smoothie.

UK consumption of avocado has soared as it has become increasingly fashionable, and M&S said sales at its stores rose 29% last year.

Hear more on the laser labelling of fruit and vegetables on the BBC World Service programme, Science in Action.