Martin Lewis has urged shoppers to compare the prices of products they are planning to buy on Black Friday to avoid overspending.

Black Friday, which officially lands on November 26 this year but extends for more than one day, is popular with many shoppers, especially as it lands right before Christmas.

However, Money Saving Expert founder Martin Lewis has given a stark warning after it was revealed last year by Which? that 85 percent of Black Friday product prices aren’t the cheapest they’ve ever been and just one percent were at their lowest ever price.

Taking to Twitter to issue the warning, Martin said: “Quick Tip. Got anything you're planning to buy during #BlackFriday promotions?

“Go and do a price check now, so you have a benchmark to see if it is really cheaper when it is 'discounted'.”

The Money Saving Expert usually warns shoppers of the problems with Black Friday, telling viewers of his show last year: "Let's take the basic premise of any discount.

"If you were planning to buy a video game for £50 and it's on sale for £25 you've saved 25 quid.

“If they have tweaked your spending nipples to buy something you wouldn't otherwise buy, there's an extra cost of £25, so it's not a saving.

"Where it's useful is, you've got a list, you know what you want, you create your list, and stores have store-wide discounts which means you can buy it 30 per cent cheaper.”

How to check the price of your product before you buy:

Google Shopping

The MSE website recommends using Google Shopping to compare product prices and find the cheapest offer and say the MSE Deals team even use it as a starting point when checking out deals.

It can search through a wide range of retailers such as Amazon, Tesco and John Lewis.

Kelkoo

Kelkoo compares thousands of offers from big brands to help you find the cheapest deal.

PriceRunner

PriceRunner checks the prices of over 2.2. million products from 6,000 UK stores so be sure to check this site before you buy that Black Friday deal.

Price Spy

Price Spy compares product prices but also has expert and user reviews to help you make an informed decision.