Is Unlimited Broadband Really Unlimited?

What Does 'Unlimited' Mean?

In the world of broadband, "unlimited" is a marketing term, and its meaning can vary. At its most basic, an unlimited broadband plan means you do not have a "hard data cap." A data cap is a fixed limit on how much data you can download or upload each month (e.g., 100GB). If you go over this limit, you're often charged extra fees.

So, an "unlimited" plan means you can browse, stream, and download without watching a data meter or worrying about surprise charges on your bill. For the vast majority of users, this is the most important feature. However, "unlimited" doesn't always mean "no limits of any kind."

The Catch: Fair Usage Policies (FUP)

This is the most common "catch" with unlimited plans. A Fair Usage Policy (FUP) is a clause in your contract that allows the provider to manage their network. It's designed to stop a tiny minority of extremely heavy users from negatively impacting the internet experience for everyone else on the same network.

Imagine your street shares a single large water pipe. If one house decides to run 50 hoses 24/7, the water pressure for everyone else will drop. A FUP is the water company's right to ask that one house to cut back. In broadband terms, this "cutting back" usually means throttling, or slowing down, your internet speed for a period.

• Who is a "heavy user"? This is usually an extremely high bar. We're not talking about a family streaming 4K Netflix every night. We're talking about users downloading terabytes of data, often through automated P2P file-sharing, or running commercial servers on a residential line.
• What happens? If you trigger a FUP, you won't be fined. Your provider will likely slow your connection down, either for the rest of the day or during peak hours.

Traffic Management Explained

Traffic Management (or "traffic shaping") is a more active version of a FUP. Some providers will automatically slow down specific *types* of internet activity during peak hours (usually 8 PM - 10 PM) to keep the network stable for everyone.

For example, a provider might prioritise video streaming (like Netflix or BBC iPlayer) and online gaming (like Call of Duty) to ensure they run smoothly, while temporarily slowing down less time-sensitive activities like P2P file sharing, large software updates, or cloud backups. This is less common than it used to be, especially on modern full-fibre (FTTP) plans, but some providers still use it.

Broadband Policy Types Compared

Here’s a quick breakdown of the different types of "unlimited" plans you might encounter, from best to worst.

Are There 'Truly' Unlimited Plans?

Yes, they do exist and are becoming more common. Thanks to consumer pressure and regulations from Ofcom, many major providers have moved to "truly unlimited" plans, meaning they have no Fair Usage Policies or traffic management.

Providers built on the new full-fibre network (like Zen, Hyperoptic, and Community Fibre) almost always offer truly unlimited services because their networks have much more capacity. Many larger providers like Sky and BT also offer unlimited plans with no meaningful FUP for standard residential use.

Are You a 'Heavy User'? A Checklist

Worried you might be one of the "heavy users" affected by these policies? Here's a quick checklist. If you answer "yes" to these, you *might* want to read the FUP. If not, you have nothing to worry about.

A Note on 'Unlimited' Mobile Broadband

Be extra careful with "unlimited" plans for 4G or 5G mobile broadband (including SIMs for your phone). Because mobile networks have less capacity than fixed lines, their Fair Usage Policies are often much stricter.

It's common to see a mobile "unlimited" plan with a FUP of 650GB per month. While this is still a huge amount of data, it's not "truly" unlimited and is a limit you *could* hit if you use it as your main home internet connection.

How to Check Your Provider's Policy

Providers are required to be transparent about their policies. Before you sign up, look for the "Key Facts Indicator" or "Broadband Facts" sheet. This is a simple, one-page document that must clearly state if there is a Fair Usage Policy or traffic management. If you can't find it, check the full terms and conditions (T&Cs) on their website.