How to check UK phone numbers against TPS and CTPS before a calling campaign

To check UK phone numbers against TPS and CTPS before a calling campaign, screen your entire list against both the Telephone Preference Service (TPS) and Corporate Telephone Preference Service (CTPS) registers using a bulk screening tool, either by uploading your file to a drag-and-drop portal or by connecting an API for real-time checks at the point of capture. You must screen against both registers rather than one, because sole traders and some partnerships register with the TPS whilst limited companies and other corporate bodies register with the CTPS. Re-screen at least every 28 days, as a new registration takes 28 days to take effect and the registers change every day.

That is the short answer. The rest of this guide covers what each register holds, what the law requires, how screening works, and what else to check before your team starts dialling.

What are TPS and CTPS, and why do you need to check both?

Both are official UK opt-out registers for unsolicited marketing calls. They are run by the same operator, work in much the same way, and cover completely different sets of numbers. That last point is where most calling campaigns come unstuck.

TPS (Telephone Preference Service) is for consumers

The Telephone Preference Service is the register where individuals record that they do not want to receive unsolicited sales and marketing calls. Anyone with a UK landline or mobile can add their number for free.

Crucially, the TPS is not only for people at home. Under the Privacy and Electronic Communications Regulations (PECR), sole traders, partnerships in England, Wales and Northern Ireland that are not limited liability partnerships, and other unincorporated businesses all count as individual subscribers. That means a one-person consultancy or a high street plumber will register their business number with the TPS, not the CTPS. If you are running B2B outreach and you assume the TPS is irrelevant to you, you will call them anyway.

CTPS (Corporate Telephone Preference Service) is for businesses

The Corporate Telephone Preference Service is the equivalent register for corporate subscribers. That covers limited companies, limited liability partnerships (LLPs), Scottish partnerships, some government bodies and any other entity with its own separate legal status.

A CTPS registration applies to specific numbers rather than a whole organisation, so a company’s switchboard can be registered whilst a direct dial is not. There is no reliable way to guess. You screen, or you find out when a complaint lands.

Why a TPS-clean list is not automatically CTPS-clean

The registers hold separate data. A number screened against the TPS only has been checked against the consumer opt-out list, so any corporate opt-out sitting on the CTPS is still invisible to you.

The ICO puts this plainly in its business-to-business guidance: “some businesses (eg sole traders and some partnerships) register with the TPS, and others register with the CTPS. Therefore before you make live B2B calls, you need to screen against both the CTPS and TPS registers, as well as your own ‘do not call’ list.”

Note the third item. Your own suppression list, or do not call (DNC) list, sits alongside the two public registers. Someone who asked your team not to ring again will not appear on the TPS or CTPS, and calling them anyway is the fastest route to a complaint.

What does PECR say about calling TPS/CTPS-registered numbers?

PECR sits alongside UK GDPR and governs marketing by phone, email, text and post. For live marketing calls, the position is straightforward.

You must not make unsolicited live marketing calls to a number registered with the TPS or CTPS unless that subscriber has specifically told you they are happy to hear from you. The ICO is clear that this needs a proactive step from the subscriber, giving a clear signal that they agree to your calls. Failing to opt out is not the same as agreeing to be called.

Two practical points follow. The obligation to screen sits with you, the caller, and does not transfer to whoever supplied the data. And if you buy or rent a list the supplier says is already screened, ask when that happened, because a registration made since then may now be live.

The stakes went up this year. Since 5 February 2026, when the relevant provisions of the Data (Use and Access) Act 2025 came into force, the maximum penalty for a PECR breach has risen from £500,000 to £17.5 million or 4% of global turnover, whichever is higher, bringing PECR into line with UK GDPR. The full rules are set out in the ICO’s guidance on direct marketing using live calls, and the DMA’s preference services guidance is a useful companion on best practice.

The commercial argument is simpler. Complaints damage your brand and occupy your compliance team, and screening removes numbers that were never going to convert anyway.

How to screen a calling list against TPS and CTPS

There are two sensible ways to do this. The right one depends on whether your data arrives in batches or one record at a time.

Option 1: drag-and-drop bulk upload (no technical knowledge needed)

This is the standard approach for a campaign list. Export your numbers to a CSV or Excel file, upload it to the Data Soap portal, and run a combined TPS, CTPS and DNC check in a single pass.

The file comes back flagged, so you can see which numbers are registered and which are legal to call. Suppress the registered ones, import the clean list into your dialler, and your team starts the day on numbers they are allowed to ring. No IT ticket, no developer, no spreadsheet formulas, and minutes rather than days.

Option 2: API integration for real-time checking at the point of capture

If leads arrive continuously through web forms, partner feeds or a CRM, batch screening leaves a gap. A number captured this morning may be called this afternoon, long before the next bulk check.

The Data Soap API solves that by checking each number the moment it enters your system. A lead sitting on the TPS or CTPS register is flagged straight away, so it never reaches a dialler queue. It is RESTful, and your developers can wire it into a lead form or CRM without a rebuild.

Many teams use both: the API keeps new data clean at the point of capture, and bulk screening keeps the existing database honest.

How often should you re-check? Lists update constantly

This is not a one-off task, and the most common compliance mistake is treating it like one.

A new TPS or CTPS registration takes 28 days to take effect, and people register every day. A list screened three months ago is not a screened list, it is an out of date one. Screening every 28 days is the benchmark most compliance leads work to, and screening immediately before each campaign launch is better still.

Your contact data is decaying for other reasons too. People change jobs, businesses close, numbers get reassigned. Our plain-English guide to data cleaning covers how fast a database degrades and what to do about it.

What else should you check before a calling campaign?

TPS and CTPS screening tells you which numbers are legal to call. It says nothing about which ones actually work. Three further checks belong in the same pre-campaign routine.

HLR Lookup for dead mobile numbers. HLR stands for Home Location Register, the mobile networks’ live record of which numbers are active. An HLR Lookup asks the network in real time whether a mobile is reachable, catching disconnected SIMs, fake numbers typed into web forms and numbers ported to another network. Every dead mobile you remove is dialler time your agents spend on a real conversation instead.

Enhanced Landline Validation. The same idea for UK landlines. It confirms whether a number is valid, active and accepting calls, stripping out disconnected lines and numbers that ring out forever.

Your own DNC list. Internal opt-outs are your responsibility and are not covered by TPS or CTPS. Data Soap lets you manage your suppression list in the same portal and screen against it in the same pass.

Run all four together and you get a list that is both legal to call and actually worth calling.

Frequently asked questions

Is CTPS the same as TPS?

No. The TPS is the opt-out register for individual subscribers, which includes consumers, sole traders and partnerships in England, Wales and Northern Ireland that are not LLPs. The CTPS is the separate register for corporate subscribers such as limited companies, LLPs, Scottish partnerships and some government bodies. They hold different data, so screening against one does not clear a number against the other.

Do I need to check CTPS for B2B calls?

Yes, and you need to check the TPS as well. Business numbers appear on both registers depending on how the business is legally constituted, and you cannot tell which applies by looking at the number. The ICO’s guidance tells B2B callers to screen against both, plus their own do not call list.

How do I bulk check a list of phone numbers against TPS?

Export your numbers to a CSV or Excel file and upload it to a bulk screening tool. Data Soap’s portal screens the whole file against TPS, CTPS and your internal DNC list in one pass, returning it with each number flagged so you can suppress the registered ones before importing to your dialler. No technical skills are required. For continuous checking, the API does the same job one record at a time.

How much does a TPS/CTPS check cost?

Data Soap uses volume-based pricing, so the per-record cost falls as your volumes rise. New customers can start with the £4.99 starter pack, which provides £100 of data cleaning credits: a low-risk way to screen a real list. See Data Soap pricing or call 0207 856 0422 for a volume quote.

Key takeaway

To screen a UK calling list properly, check every number against both the TPS and the CTPS registers plus your own do not call list, using bulk upload for campaign files or an API for real-time checks at the point of capture, and re-screen at least every 28 days because registrations take up to 28 days to activate. Screening both registers rather than one is the step most teams miss, and it is the difference between a campaign that is legal to run and one that generates complaints.

Ready to clean your list before your next campaign? Start with a TPS and CTPS check, or if you are new to Data Soap, take the £4.99 starter pack and find out how many of your numbers you should not be calling.