JumpLead
Interactive tool · Find your buyer
The ICP Builder: your ideal customer, on one page
Chris May and Joe Stone
Interactive tool · Find your buyer
The ICP BuilderYour ideal customer, on one page.
Chris May and Joe Stone
- Updated October 2026
- About 30 minutes, in one go or several
- Answers stay in your browser
Chapter 01Start here
Start with the customersyou’ve already won.
Don’t invent a buyer in a meeting room. The best evidence you have is the people who already said yes. Pick your three best recent customers: the ones you’d most like more of, whatever their size.
Use the job title of the person who signed. It’s often someone other than the person you first emailed. And write down why they chose you in their own words, because those words go into your messages later.
Three is enough to see a pattern.
Read across: what repeats?
Who signed?
Customer 1: Not yet
Customer 2: Not yet
Customer 3: Not yet
What was happening?
Customer 1: Not yet
Customer 2: Not yet
Customer 3: Not yet
Why you?
Customer 1: Not yet
Customer 2: Not yet
Customer 3: Not yet
Answers save in this browser as you type. Nothing leaves it until you ask us to email your one-pager.
Look for
Two answers out of three that match. That’s your first pattern. If nothing matches, you may have more than one ICP: pick the one you’d most like more of, and start there.
Chapter 02Write it down
Your ICPin one sentence.
A pattern isn’t a target yet. The sentence below makes you decide five things. Each one is something you can filter a list on, or something you can open a message with.
“Finance leaders at mid-sized UK companies.”
No sector to search, no size to filter on, no reason to call this month.
“Haulage firms in the Midlands with 50 to 250 staff that have just added a depot, and need drivers on the road faster.”
Every part either narrows the list or hands you an opening line. (An example of the shape, not a customer of ours.)
what they do where with how big that what’s just happened, and what they need.
Sharp enough to build a list from?
0 of 5
- Names a real sector: not yet
- Says where: not yet
- Gives a size you can filter on: not yet
- Names something that just happened: not yet
- Says what they need, in their words: not yet
Keep in mind
If you change the sentence, change the offer and the message with it. A message written for one sentence won’t land with the other two.
Chapter 03The buying group
Who signs, who uses,who blocks.
Most B2B deals need more than one person to agree. Name the three that matter and what each one needs. You’ll write to the first, win over the second, and answer the third before they ask.
- 1
Signs
Owns the budget and says yes.
- 2
Uses
Lives with it every day.
- 3
Blocks
Can stop it, even if they can’t start it.
Who to write to
The person who feels the problem first. That’s often not the person who signs, and they’ll take you to the one who does.
Chapter 04Say no early
Who to leave outso the list stays sharp.
Leaving companies out keeps every message pointed at someone who could buy. Switch on the rules that apply to you. One of them is the law: for email, the ICO treats sole traders and some partnerships as individuals, so you need their consent first.
Chapter 05Free UK data
Count your marketbefore you write a word.
You don’t need a paid database to know how big your market is. Three free sources get you most of the way.
- 1
Find your SIC codes. Every UK company tells Companies House what it does with one or more SIC codes. Look up your three best customers: the codes sit under “Nature of business” on each company’s page. Companies House still uses the 2007 list, even though the ONS has published a 2026 update.
- 2
Count the active companies. Companies House advanced search filters by SIC code, registered address and status, and tells you how many companies match. You can download the first 5,000 as a spreadsheet, free and without an account.
- 3
Size it. Companies House doesn’t hold staff numbers. The ONS counts businesses by SIC code, size band and area in UK Business Counts, free on Nomis. It covers businesses registered for VAT or PAYE.
Five digits each, commas between.
- Active companies in your SIC codes·
- Of those, the size you sell to·
- After leaving out (chapter 4)·
Add your count after leaving out, and this tells you how long the list lasts.
A caution
Companies pick their own codes, and the registered office isn’t always where they trade. Treat the count as a good guide rather than an exact figure.
Chapter 06Timing
Signals that say“now”.
A company can match your sentence perfectly and still have no reason to talk this month. These free UK sources show when something has changed inside one. Switch on the two or three you’ll really check each week.
Companies House
Search the registerNew shares allotted
Form SH01 tells Companies House that a company has issued new shares since it was set up.
New shares often mean new investment, and new investment usually comes with a plan to spend it.
A new director
Form AP01 records the appointment of a new director and the date they started.
A new name at the top is a fair reason to say hello, and to ask what’s on their list.
A change of control
PSC filings record who has significant control (PSC01), changes to their details (PSC04) and when someone stops (PSC07).
A new owner or investor is a reason to look again: their priorities needn’t be the last owner’s.
Find a Tender
Search tendersA public tender
Since 24 February 2025, new public contracts in England, Wales and Northern Ireland go on Find a Tender, from early pipeline notices to the tender itself. Search and alerts are free.
If you sell to public bodies, or to the firms that supply them, it’s the earliest sight you’ll get.
A public contract won
Contract award notices say who won the work.
A firm that has just won a contract has to deliver it, often with help it doesn’t have yet.
UKRI Gateway to Research
Search projectsA research or innovation grant
Publicly funded projects, Innovate UK grants included: the lead organisation, the partners, the funded value and the dates.
Funded work comes with a budget and a deadline.
The Gazette
Search noticesA rival in trouble
Insolvency notices: winding-up petitions, administrations and liquidations. Searching is free.
If a competitor fails, its customers need someone new. If a prospect appears there, take them off your list.
Their own website
Hiring for the problem you solve
Their careers page and job ads say which roles they’re trying to fill.
A job ad for the work you do, or the work you make easier, says the problem is live this quarter.
Switch on the two or three you’ll really check, and they land here.
Let them come to you
Follow the companies on your list and Companies House emails you whenever one of them files. It’s free, with an account (Companies House).
Chapter 07Prove it
Test it in 30 daysbefore you scale it.
Before you spend months on it, test the sentence on a small list: 150 to 400 contacts in your sharpest segment, checked by hand. Small enough to read every reply, big enough to hear the same objection twice.
Days 1 to 14
Set up
Separate sending domains, never your main one. SPF, DKIM and DMARC on each. New mailboxes warmed up. Your list built and checked by hand.
Days 15 to 28
Send and read
A few plain-text emails a day from each mailbox to the test list. Read every reply, and write down every objection word for word.
Days 29 and 30
Decide
Keep the sentence, sharpen it, or swap it for your second-best pattern. Then, and only then, add volume.
The rules every sender has to meet
- SPF
- PASS1
- DKIM
- PASS1
- DMARC
- PASS1
- List-Unsubscribe-Post
- One-Click2
1Since February 2024, Google and Yahoo have asked bulk senders for SPF, DKIM and DMARC, and to keep spam complaints under 0.3%. Since 5 May 2025, Outlook has rejected mail that fails them from senders of more than 5,000 emails a day.
2Gmail and Yahoo also want a one-click unsubscribe. Honour it, and keep your own list of people who’ve said no.
PECR, in short
You can email people at limited companies without their consent first, as long as you say who you are and give them a simple way to opt out, says the ICO. Sole traders and some partnerships count as individuals. If you add calls later, screen every number against the TPS and CTPS and show your number (ICO). Since 5 February 2026, fines can reach £17.5 million or 4% of global turnover, whichever is higher (Data Protection Act 2018, s.157).
Your test
Measure
Count replies. Apple’s Mail Privacy Protection loads messages privately in the background, so an “open” doesn’t mean a person read it.
Chapter 08Keep it
Your ICPon a page.
Everything you’ve written, on one sheet. Print it, pin it up and check every new list against it. Look at it again each quarter: your best customers change, and this should change with them.
The ICP Builder
Your ICP on a page
- Who we sell to
Chapter 2 writes this sentence.
- Best customers
Your three best customers from chapter 1.
- Who signs, uses, blocks
The three people in every deal, from chapter 3.
- Leave out
Who never goes on the list, from chapter 4.
- Market size
Your count from Companies House, chapter 5.
- Signals to watch
The signals you’ll check each week, chapter 6.
- The 30-day test
Your list, start date and what counts as working, chapter 7.
JumpLead · jumplead.io/resources/icp-validation-protocolReview it every quarter
Sources
Every source checked on 9 October 2026. This is guidance, not legal advice.
- Companies House, Advanced company search (SIC code, address, status; result counts; CSV of the first 5,000)
- Companies House, Nature of business: SIC codes (the 2007 list it uses)
- ONS, UK SIC 2026 (published 2026, not yet used by Companies House)
- Companies House, Searching the register (free data, following a company)
- Nomis (ONS), UK Business Counts: businesses by SIC code, size band and area, 2026
- Companies House, Return of allotment of shares (SH01)
- Companies House, Appoint a director (AP01)
- Companies House, Give notice of individual person with significant control (PSC01)
- Find a Tender, the UK’s public procurement notices since 24 February 2025
- Find a Tender, notice types (pipeline to contract award)
- The Gazette, Insolvency notices
- UKRI, Gateway to Research (funded projects, including Innovate UK)
- Google, Email sender guidelines
- Yahoo, Sender best practices
- Microsoft, Outlook’s requirements for high-volume senders (2 April 2025)
- ICO, Business-to-business marketing
- ICO, The rules on live direct marketing calls
- Data Protection Act 2018, section 157 (maximum fines, as amended)
- Apple, Mail Privacy Protection on iPhone
Want a second pair of eyes on it? Book a free 30-minute call. Bring your one-pager and we’ll tell you what we’d test first.
Did you find this helpful?