Marks & Spencer has agreed to make the packaging of all of its toys gender neutral by spring 2014, after customers complained that it was marketing items according to stereotypes.

Customers contacted M&S to complain at a range of toys called "Boy's Stuff", which included planes, cars, dinosaurs, racing cars, cat toys, a marble run and a pop-up fire station.

The description on the latter said: "This pop up fire station is perfect for little fire men everywhere", while the description of a watch in the same range read: "The perfect wrist accessory no boy should be without," and a joke book read: "Boys know the best jokes and here are 500 crackers to keep you ahead of the girls."

The Boy's Stuff range will be rebranded to use a simple graphic logo, while the "Little Miss Arty" range will become "Poppy and Blue", using character-based branding.

M&S told the Guardian it was already in the process of updating its policy but this became public when it responded to a specific criticism on Twitter by Labour MP Stella Creasy. It Tweeted back: "Hi Stella, we've listened to customer feedback and by spring next year all of our toys will be gender neutral. Thanks."

M&S said in a statement: "We offer a wide range of fun and educational toys, which are designed to appeal to children regardless of gender. We have listened carefully to feedback from our customers and by spring next year all of our toys will be gender neutral."

Meanwhile, the number of shops organising their toy departments into separate sections for boys and girls has fallen by 60% in the past year, following pressure on retailers from shoppers and campaigners, it has been claimed.

Campaign group Let Toys be Toys said reports from the high street suggested that a fifth of stores were still organising their toy sections by gender rather than genre, compared to half in the runup to Christmas 2012.

The group, which started in November 2012, has been calling on retailers to end gender-stereotyping in toy departments which has seen some display play kitchens and colouring sets under "girls" signs and science sets and doctor's costumers under "boys" signs.