London AI voice agent agency

A London agency that builds AI voice agents.

Legacy AI is a London-based agency that builds custom AI voice agents, chat agents and automations for small and mid-sized businesses. We have 100+ agents live for 52+ companies in the UK, the US, Canada, Europe and Australia, and most builds launch in 3 to 4 weeks at a fixed quote.

Last updated 11 November 2026 · Legacy AI, London

What we build.

AI voice agents that answer inbound calls 24/7, take orders, book jobs into your calendar and CRM, and hand urgent calls to a person.

Outbound AI callers that phone new leads, qualify them and book appointments.

Chat agents for your website, WhatsApp, SMS and email.

Automations that connect your ERP, CRM, booking system and inbox.

We build on Retell (we're a Gold Retell Partner), ElevenLabs, Vapi, LiveKit, Voiceflow, n8n, OpenAI and Anthropic Claude, and we pick the platform that fits the job.

Most of our buyers already have a system the agent has to work inside. For Refund Advisory in Texas, the voice agent looks callers up in their own database through their Partner API and updates their record during the call.

Voice agents for London businesses.

Two of our London builds:

Thames Building Supplies, an East London builders' merchant: a phone-ordering agent that reads live stock and account pricing from their ERP and speaks English, Punjabi and Hindi (in build now).

Panda & Partners, a London lettings agency: instant replies to Rightmove and Zoopla enquiries and viewings booked automatically. Gerald Chan: "everything is quicker in a sense."

How to choose an AI voice agent agency.

Most agencies can make a demo that sounds good. What matters is whether the agent works inside your systems on a busy Monday. Ask every agency you speak to for these, and compare the answers. Here are ours.

What to ask	Legacy AI
Agents live	100+ for 52+ companies
Where you're based	London, with clients in the UK, US, Canada, Europe and Australia
Time to launch	3 to 4 weeks for most builds
Pricing	Fixed quote, agreed before we start
Connects to your systems	Yes: ERPs, CRMs, booking systems, calendars and partner APIs
Languages	English plus your customers' languages, with mid-call switching
Named clients you can check	Venture Home, Osmow's Shawarma, BookRetreats, Ski With Ease, Panda & Partners and more
After launch	Maintained and improved month to month

How a build runs.

A 30-minute discovery call, free. We find the biggest wins in your calls and tell you straight if AI isn't the answer.

A fixed quote, agreed before we start.

Launch in 3 to 4 weeks for most builds, tested on real conversations before go-live. Builds that connect to an ERP or a partner API can take longer, and we say so up front.

We maintain and improve the agent month to month from live calls.

Clients you can check.

Venture Home

RESIDENTIAL SOLAR · US · 13 STATES

Built: An inbound voice agent that answers questions about the company and its process, an AI layer over their new CRM, and a tool that pulls energy usage straight from customer utility bills.

In their words
"That is probably the best AI voice I've heard. Like, just realistic sounding."
Alex Yackery, Co-Founder, Venture Home

Refund Advisory

IN BUILD NOW

REFUND RECOVERY · TEXAS

Built: A voice agent on their phone lines. It looks the caller up in their own database through their Partner API, confirms who they are, answers questions about their case, updates their phone number and routes calls to staff through Nextiva.

Panda & Partners

PROPERTY LETTINGS · LONDON

Built: Nine connected workflows across the lettings process: instant replies to Rightmove and Zoopla enquiries, a WhatsApp group per applicant, viewings booked around the current tenant with reminders, offer intake, and landlord accept, reject or counter.

Result: More enquiries answered and more viewings booked, with less staff time.

In their words
"I'm seeing, you know, better results already in terms of inquiries are actually being answered, people are arranging viewings, etc. And with actually less human involvement, everything is quicker in a sense."
Gerald Chan, Panda & Partners

Ski With Ease

SKI SCHOOL · FRENCH ALPS · 35 INSTRUCTORS

Built: An AI that drafts booking replies from live instructor availability for the team to send, an email sorter with a to-do list, and a calendar sync for a booking system with no API.

Result: 32 hours a week of email admin taken on, saving around £2,000 a month.

BookRetreats

RETREAT MARKETPLACE · GLOBAL

Built: A sales chat agent that runs a discovery conversation, recommends the right retreats and handles objections on the way to booking.

Result: Cost per conversation down from $5 to $15 to around $0.50.