Do you buy things you don't really need?

Have you ever wondered why sweets are always by the till in supermarkets? Why you are made to walk down many aisles to reach the everyday essentials at the back of the shop?

Retailers are always coming up with new tactics to get us impulse buying.

The BBC's Denise Winterman reveals some of the ways in which they try to trick us into buying what we might not really need.

One of them is messing up the merchandise. Some shop assistants do it on purpose to give the impression that these are must-haves, which lots of people have been looking at.

Companies are also trying to gather and analyse data from an individual's financial transactions, social media posts and mobile phone signals. They're planning to personalise offers for individual customers by using GPS location data to target them when they are actually walking past one of their shops.

And eye-tracking technology is the latest weapon in the fight for customers. In some shops, digital screens behind luxury brand display stands are activated when a perfume bottle is picked up, flashing seductive images. Eye-tracking systems are fixed into screens to gather data so the images can be personalised. It's all done in seconds.

Paula Dowie from the retail design agency Ignite Design says: "Certain software programs can gather huge amounts of data on you almost instantly. Age, gender, what you're looking at... If you're a young women or a middle-aged man... Images are then flashed up that will appeal to you."

It's about entertainment and making a shop one that people want to enter. Brands like Apple and Top Shop are "genius" at doing this, says Joseph Staton, director of GfK Consumer Trends. During London Fashion Week, Top Shop screened its own fashion shows live in its flagship store in London's Oxford Street.

"It's about offering things like art and music as part of the shopping experience," says Staton.