A guide to internet throttling

Author: Jamie Kavanagh

Last updated: 04 March 2025

Internet throttling is when your broadband provider slows down certain types of web traffic on purpose, usually part of traffic management. This is also known as ‘traffic shaping’.

Throttling is used to make sure video calls and streaming run smoothly, especially during peak hours.

If the network is busy, the provider can identify the type of traffic slowing everyone down and limit that traffic.

The idea is to keep traffic flowing as fast as the network allows. This is so everyone gets some service even if it isn’t the high speeds you expect.

Traffic management is a murky area. Providers say they don’t do it, but some of our experiences say otherwise.

So what’s the truth? What causes your connection to slow down or videos to stream at lower quality? Let's explore...

What is unlimited broadband?

When an internet plan is labelled as being ‘unlimited’ it means there’s no data cap and no restrictions on how you use your connection.

You can download, stream, and upload as much as you want without worrying about hitting a data usage limit, getting charged extra, or having your connection cut off.

But here’s the catch—unlimited doesn’t always mean completely unrestricted.

There may, or may not, be fair usage caps or traffic management depending on your internet provider.

Some providers may use traffic management during busy times, especially if you’re a heavy internet user or share your connection with family or housemates.

So you may have ‘unlimited’ data, but the speed at which you can access that data may be limited at certain times.

Why would an ISP use throttling?

ISPs can throttle internet speeds for many reasons. While providers say they don’t use traffic management, many users remain unconvinced.

Here’s just a few:

• Managing congestion: Enforces bandwidth limits for certain users or services, so the whole network doesn’t grind to a halt.
• Keeping things fair: Internet throttling prevents a handful of heavy users from hogging all the bandwidth and slowing everyone else down.
• Enforcing data caps: If you hit your monthly data limit, a provider might slow you down to convince you to upgrade your plan or keep excessive use in check.
• Prioritising important traffic: Emergency calls, VoIP services, or work-related apps need priority over things like Netflix or gaming.
• Making money: Throttling can also be a business move. Slower speeds can encourage you to upgrade to pricier, less-restrictive options.
• Working with old infrastructure: Some areas just don’t have the capacity for high-speed internet across the board, so ISPs use throttling to manage what’s available.
• Managing faults or planned work: Networks are very complicated and faults happen a lot. A provider may use throttling to manage congestion whole a fault is being fixed or equipment is upgraded.

How does internet throttling affect you?

Internet throttling can impact you in several ways, depending on how you use your connection.

• Streaming: Reduced bandwidth may lead to buffering, lower video quality, or longer load times. High-resolution streams could drop to lower resolutions.
• Gaming: Increased latency and higher ping can affect game responsiveness. You might experience delays in character movement or slower reaction times in fast-paced games.
• Video calling:  Slower internet speed may cause choppy video, frozen screens, or delayed audio.
• Working from home: Large files may take longer to upload, and remote desktop performance could be impacted.
• General browsing and downloads: Web pages and software updates may load slower than usual.

While ISP throttling is often used for network management, I’s usually kept to a minimum. Sometimes, you won’t notice, other times you will!

How do you know if you’re being throttled?

There are several giveaway signs that your ISP may be throttling your connection.

They do not prove anything, but they can prompt you to investigate further.

They include:

• Slow connection speed at peak times: If your internet is much slower than usual, especially during peak hours, throttling could be the cause.
• Slowdowns on specific activities: Streaming, gaming, or downloading may be much slower while general browsing seems fine.
• Buffering and lower quality streams: Videos drop to lower resolutions (e.g., 4K to 720p) or buffer frequently despite having a high-speed plan.
• High ping and lag in online games: Sudden spikes in ping or lag can indicate bandwidth restrictions, especially if other devices aren’t using the network heavily.
• Fast speed tests but slow real-world performance: Speed test results show high speeds, but downloads, streaming, and gaming still feel sluggish.
• Slow uploads and cloud syncing – Large file uploads to services like Google Drive or Dropbox take much longer than expected.

If multiple signs match your experience, your ISP may be throttling your connection.

It may also be a fault, a high traffic event, planned works or something else, so more investigation may be required.

Which broadband providers use throttling?

Here's a summary of traffic management policies for major UK ISPs:

While the major ISPs don’t use internet throttling, they may have acceptable use policies which may impact speed.

Check with your provider if you’re unsure.

What can I do if I suspect my broadband isn’t truly unlimited?

If you suspect your broadband is being throttled or limited in any way, you need to gather evidence.

There are so many moving parts that make the internet work, it could be any number of things.

Before contacting your provider:

• Make sure it’s a repeating occurrence, not just a one off
• Test multiple websites, games or streaming services to verify it’s a provider issue
• Use the Broadband Genie speed test to see if you’re getting advertised speeds
• Check both wired and Wi-Fi connections in case it’s a wireless issue
• Check the amount of data use traffic on your router or via your online dashboard
• Check your ISP for network faults or planned works in your area
• Check your ISPs policy on speed and data limiting
• Check the Ofcom code of practice so you know your rights

Gathering evidence is essential when engaging with broadband providers.  The more you can show you know what you’re talking about, the more likely you are to get a satisfactory result.

Give your ISP time to investigate and address the issue.

If they come back with a solution or identify network congestion as the cause, they should ideally do something about it.

If they come back without a solution, ask them for next steps, as it’s their responsibility to deliver the quality of service you’re paying for.

Want to share your experiences with others? Sign up to join our broadband community!

Internet throttling FAQs

• Does Virgin carry out throttling?

  Virgin Media’s traffic policy says it doesn’t throttle traffic or use traffic management. Slowdowns in internet connections can be common and nothing to do with ISP throttling. It can be caused by network congestions, network faults, planned works on networks and many other reasons.

• What are the signs of internet throttling?

  The signs of internet throttling include websites loading slowly or being inaccessible, slow download speeds, buffering on music or video streams, lower quality video streams, high ping on games and delays with any online activity.

  There are many signs of bandwidth throttling, but they are also signs of other network issues such as congestion or faults.

• Is it illegal for my ISP to throttle my internet?

  No, it is not illegal for an ISP to throttle your internet connection. It isn’t illegal as long as the internet service provider follows net neutrality rules and isn’t unfairly prioritizing some types of traffic over others or throttling particular services without good cause.

  If providers use throttling, they must be transparent about it, have a good justification and use it sparingly and only when absolutely necessary.

• Will a VPN stop throttling?

  A VPN can stop throttling if a provider is controlling specific internet traffic or services. For example, an internet service provider may want to throttle heavy downloaders so could restrict bit torrent traffic. Hiding that traffic within a virtual private network could work around it.

  However, if bandwidth throttling is being used to protect the network or work around a fault, a VPN won’t make any difference.

• Can internet throttling affect streaming quality?

  Yes, internet throttling can affect streaming quality. Video streams use a lot of bandwidth so you may see a reduction in quality if throttling is being used. For example, a 4K stream may be reduced to 1080p or 720p.

  Poor streaming quality can also be down to congestion at the provider’s end or a low-quality upload if it’s YouTube or another platform. It isn’t always bandwidth throttling that’s the issue!

Quick summary

Just because your internet slows down, doesn’t mean your provider is using throttling or traffic management.

Slow internet speeds can be down to your router, other users in your home, high traffic events (such as Taylor Swift tickets going on sale) the website you’re using, a network fault, planned works on the network and many other reasons.

If you have performed your checks and think it’s your provider, gather your evidence and ask them.

It may not be ISP throttling but highlighting the fact you’re not getting advertised speeds is something they have to deal with.

Whether you’re unlimited or not, you should always get what you’re paying for!

Sick of sluggish speeds? If you're out of contract, switching providers is the easiest way to get a boost. Find a faster package today!