How to Brief an Event Planning Company in London

A great event starts with a great brief, and your brief is the most powerful tool you have for a hitch-free result.

The essentials are simple: objectives, audience, budget range, date, guest numbers, event type, and a steer on the look and feel.

You don’t need experience or an expertly written document. A good agency partner asks the right questions, soundboards, and fills the gaps with you.

The clearer your brief, the less back-and-forth there is, the fewer surprises crop up, and the more creative freedom your agency has.

At Story Events, we take briefs from a single line through to full production, handling venue, AV, decor, catering and logistics so you don’t have to.

When you’re handed a major event to organise on top of everything else on your plate, it can feel like a lot. You might be an EA, a PA, a marketing lead or part of an HR team, and chances are this is one job among many. Perhaps you’ve never run an event of this scale before, or you’re simply snowed under with competing priorities, so you’ve decided to bring in a London event planning company to ensure event success.

Over more than a decade of delivering events across London, we’ve learned something crucial: how you brief your event planning company is the foundation for everything else. 

A clear brief ensures we are aligned with your vision from day one. And while it might feel like the boring admin bit, it’s the single most useful thing you can do to guarantee a successful event.

1. It cuts down the endless email back-and-forth, because the answers are already pulled into a single place.
2. It agrees on expectations up front, which prevents nasty surprises or a mismatch in what’s required.
3. It gets everyone aligned, including your CMO, your CEO and your HR director, who each have a slightly different idea of what success looks like.

In short, the criteria for your event are settled on paper, rather than halfway through planning.

Think of your brief, then, not as a chore you’ve been lumbered with, but as the way you stay firmly in control of an event you’re trusting someone else to deliver.

Let’s clear up a common worry before we go further. Your brief is your vision and your non-negotiables. You own the what and the why. Your event planning company owns the how.

You don’t need to have a minute-by-minute plan, detailed event production schedules, or a working knowledge of projection mapping. You simply need to be clear about what a brilliant event looks like to you and your business, whether it’s a conference, Christmas party, or summer soirée. Your London event company will translate that into how the event gets built, which is the point of working with a full-service event agency in the first place. We’re across the latest event trends and have first knowledge of new venues and logistics around London.

So what does a great London event brief contain?

Start here, always. What is the event for? Are you building company culture, launching a product, rewarding a team, raising funds, generating sales pipeline, or deepening client relationships? 

Try to land on one or two measurable goals, so success isn’t a matter of opinion after the fact. When your objectives are crystal clear from the outset, everything else feeds into those goals, which is exactly what we saw with the JustGiving Awards, whose primary objective was to craft an exceptional atmosphere that celebrated 21 remarkable finalists and their inspiring fundraising efforts–work that went on to win the Event Legacy Award at the CN Agency Awards.

There really is nobody else I would trust with the brief, because you nail it every time. No problem is too big for you to handle, no worry is too small for you and the team to care. – JustGiving 

Who’s coming, and what do they expect? Tell us about seniority, numbers and any accessibility requirements. Flag early whether guests will be seated or standing (or both!), too, because that single detail changes both the venue capacity you need and the type of London venue that works.

Give us a realistic range, a low end and a high end. Guest numbers drive venue size, catering and budget more than almost anything else, so even a rough figure helps enormously at the start. Story delivers to all scales, from small numbers for boutique, luxury experiences to events with hundreds of attendees.

Is your date fixed or flexible? If it’s flexible, offer a couple of options in order of preference. Prime London dates disappear fast, particularly across December and the summer months, so the earlier you pin this down, the more choice you’ll have. Do mention any requirement for nearby overnight stays or early set-up needs as well.

Ah, the number everyone’s slightly nervous to share. We’d gently encourage you to share it anyway, because a budget range is one of the most useful things in the whole brief. It lets us shortlist realistic venues and ideas, and it tells us where to spend for the most impact. A good event partner will treat your budget as a design constraint to work cleverly within.

Conference, awards or charity dinner, product launch, brand activation, summer party, Christmas party or away day? Live, hybrid or virtual? Naming your event type instantly rules certain formats and venues in or out, which saves everyone time.

You don’t need a mood board (although we’ll happily take one). Even a loose steer helps, i.e. a blank-canvas warehouse versus a heritage ballroom, your brand colours, the feeling you want guests to leave with.

When Criteo briefed us for their first Retail Media Summit, the request was essentially “find us a striking, central London venue.” From that, we sourced BAFTA at 195 Piccadilly and built the rest around it, including bespoke projection mapping, registration, catering and a drinks reception in the Richard Attenborough Room. Afterwards, the client told us we’d lifted the stress of event day clean off their shoulders. Their short brief was fully realised.

Story were great partners to us on this event. In particular, they sourced an amazing venue and lifted the ‘event day stress’ considerably! Story were also able to help us source the additional touches which made the event extra special and memorable for our guests. – Criteo

Finally, tell us your non-negotiables and the things to avoid at all costs. This might be a sustainability commitment, a dietary standard, strict brand guidelines, or a format that fell flat last year. References from past events are gold here, both the bits you loved and the bits you’d rather never repeat.

Objectives: what’s the event for, and how will you measure it?

Audience: who, how many, seated or standing, any access needs?

Numbers: a realistic low-to-high range

Date: fixed or flexible, plus any overnight or set-up needs

Budget: a range is absolutely fine

Event type and format: live, hybrid or virtual?

Look and feel: venue style, brand colours, the mood you want

Must-haves and no-gos, plus references from past events

Want to see a good brief in action? Take Reiss’s Retail Summit 2026. Their brief carried several clear objectives at once, and that clarity enabled us to design a truly memorable event.

This was the second year running that Reiss had trusted us with their retail summit, and the brief was ambitious. They wanted a single day spanning a conference, a fashion show and an after-party, all under one roof, and they wanted it to feel immersive and unmistakably Reiss, reflecting the brand’s own retail environment. It also came with a complex schedule and large-scale logistics, with a high volume of suppliers, product and people to coordinate.

Because we knew all of that up front, every briefed element came together. We took over Tobacco Dock and transformed the former shopping centre into a fully branded, Reiss outlet-style environment that employees recognised the moment they walked in. 

From there we ran the whole day, moving guests smoothly from the conference into the fashion show, through concept-led breakouts (including a fully built escape room!), and on to the evening after-party. We also led on content production, opening with a high-impact video that set the tone for the day. The schedule was spot on, the transitions were seamless, and the Reiss team could step back and enjoy the event.

We won’t pretend every London event needs an agency. A small, low-stakes internal get-together is often perfectly manageable in-house. But once you’re dealing with something high-profile or large-scale, such as a conference, an awards dinner, a product launch or a big summer or Christmas party, the stakes change. Your company’s reputation, your team’s morale, and important client relationships are all riding on the day going well.

The hidden costs of going it alone are your time, the supplier juggling, and the risk that the one detail you didn’t know to plan for is the one that trips you up on the day.

This is where a full-service event planning company in London can help. We absorb the supplier coordination, the AV and production, the decor, the catering and the logistics, so you stay strategic and calm rather than stuck behind the scenes with a radio and a clipboard. 

If you’re still weighing it up, our guide to what a London event agency does and our piece on how an events agency helps are good next reads.

Plenty of our favourite projects started life as a single sentence and a rough date. We’re used to asking the right questions to draw out the rest, so if all you have right now is an event type, a ballpark guest count, a budget range and a sense of what you’re trying to achieve, that’s more than enough to start a great conversation.

From there, our full range of services means your brief gets delivered. We offer free venue finding, AV production and set build, event design and theming, delegate logistics, content development, and streaming for virtual and hybrid events. Whether it’s a conference, an awards dinner, a brand activation or a summer party, we turn a rough idea into a polished, story-driven event. Simply fill out this enquiry form, and we’ll be in touch.

A great event begins with a great brief, and the best briefs come from clients who tell us exactly what success looks like, then let us handle the how. That’s the partnership we love, and it’s how we deliver events that run beautifully and do real work for your business and your culture.

If you’ve got an event on the horizon, even if it’s still just a date and a rough idea, we’d love to hear from you. Clients from JustGiving and Mars to Lush and Together for Short Lives trust us with their most important events, year after year.

Send us an enquiry, and let’s start your brief together.