The analysis found 72% of customers pay an average of £40 per month to languish on basic broadband packages, £14 per month more than the typical £26 they could be paying for an entry fibre package.

Comparison site Is My Bill Fair analysed almost 16,000 crowd-sourced bills from BT, EE, Plusnet, Sky, TalkTalk and Virgin Media home phone and broadband customers.

It found 88% of BT customers on a basic broadband package – so speeds less than 30Mb – were paying an average £49.92 per month. But with the same provider they could get entry fibre (30Mb – 60Mb) for just £29.99 or top speed fibre (over 60Mb) for £45.99.

Some 79% of TalkTalk customers were in the same boat, paying £32.93 for basic broadband when they could get entry fibre for £23.50 or top speed for £26.

Plusnet customers pay an average of £34 per month for basic broadband but they could get entry fibre for £23.99 or top speed fibre for £27.99.

And EE customers pay an average of £33.34 per month for basic broadband, but for just £25 they could get entry fibre.

While Virgin Media doesn’t offer basic broadband services, their customers are still in the same boat – 85% of customers on their entry fibre package pay £41.43, while 100Mb speeds are available for just £27.

Alex Perrin, chief executive of Is My Bill Fair, said: “It’s a bit like sitting in economy class but paying the price of a business class seat. If you don’t know what business class looks or feels like you’ll never challenge it.”

He adds that customers who have stayed on the same package for long periods of time are stuck with old technology and packages that cost more with every price hike, but never get any faster.

“There’s no guarantee you’ll get the maximum speed you’ve signed up to as this varies by the time of day and many other factors.

“However, if you’re on a basic package the fastest speed you could get is less than half of the best available speed. The problem is, for many the price doesn’t reflect this,” he added.

Data from Openreach shows 96% of the UK now has access to fibre broadband.

Perrin added: “Don’t believe the myth about whether or not you have the correct cabling in your area. Providers avoid opening up conversations around faster broadband with customers as it simply encourages people to review their package and their costings.

“It’s really a case of let sleeping dogs lie as there is a risk it will lead to the question of ‘what else can I get for free’. If you’re on a low speed and you challenge your provider you will more than likely come out with a faster broadband service at a lower price.”