A Central London Conference Venue with Presence, Not Just Capacity

St Mary’s Marylebone is a distinctive alternative to the conventional conference centre. Set within a magnificent Grade I listed building in the heart of central London, it offers organisations a venue where conferences feel memorable.

The Great Hall provides a dramatic plenary space with soaring ceilings, classical columns and natural light - an environment that elevates keynote speakers, strengthens leadership messages and creates a true sense of occasion for delegates. Unlike purpose-built venues designed for efficiency alone, St Mary’s delivers atmosphere and impact alongside professional conference functionality.

With theatre-style seating for up to 600 delegates, integrated AV, and flexible additional spaces in the Undercroft for registration, catering, networking or breakout sessions, the venue supports seamless event delivery without sacrificing character.

Ideal for flagship conferences, leadership summits and single-stream events where message and credibility matter, St Mary’s Marylebone offers a prestigious, central London setting that ensures your conference is not just attended - but remembered.

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The Undercroft: More Than a Breakout Space

Empty conference or event room with rows of wooden chairs facing a screen that displays 'st mary's MELBOURNE', a bar area at the back, and plants for decor.

Located directly beneath the Great Hall and included in your hire, the Undercroft provides a distinctive supporting space that complements the drama of the main conference hall. Far from a standard breakout area, it offers character, scale and flexibility for workshops, networking receptions, brand activations or speaker preparation. The Undercroft can be divided into two generous rooms, with three additional private spaces ideal for VIP hosting, discreet meetings, event operations or secure storage — all within the same iconic building.

Tailored Catering Solutions for Your Conference

An outdoor buffet with various salads and dishes, including potato salad, pasta salad, and a meat dish garnished with greens, displayed on a table covered with a white tablecloth and a blue and white cloth with the word "LINK".

We partner with a carefully selected range of professional caterers, offering tailored solutions from formal business lunches to dynamic networking buffets and barista-style coffee stations that keep delegates refreshed and engaged. You’re welcome to work with our trusted partners or bring your own caterer for an additional fee.

Catering
A woman standing on a stage speaking in front of an audience inside a large, historic hall with a two-level balcony. The audience is seated facing the stage, and there are chairs and tables on the stage along with plants and a water bottle.
A large audience attending a conference or presentation in a grand, well-lit hall with purple lighting. There is a stage with a speaker at a podium, multiple large screens displaying a presentation, and a drum set. The hall has high ceilings with sta
Panel discussion at a conference titled 'Vision to Victory: Inspirational CFO Journeys' with four speakers on stage, audience seated facing the stage, large screen displaying speakers' photos and names above, and banners with the conference theme on
Four people sitting on stage chairs with a beige curtain backdrop, participating in a panel discussion. One person is speaking into a microphone while the others listen. There are water bottles on a table in front of them.
A man is giving a presentation in a conference room with stained glass windows, some seated audience members, and electronic screens displaying information.
A man giving a presentation in front of a room full of people, with a large screen behind him showing images of a crowd at a concert and children in a classroom.
Conference or panel event taking place in a large hall with tiered seating, a stage with four people seated and a large screen behind them, and an organ with pipes on the right side of the upper level. Many attendees are seated at tables, and there a
A large group of people inside a spacious, elegant hall with a high, decorative ceiling, posing for a group photo. Two individuals stand at the front center, smiling and holding a certificate or paper, with the group behind them.
Floor plan of a large auditorium called The Great Hall, featuring a stage at the front, rows of seating, a carpeted aisle, altar at the back, and various rooms including a drum booth, altar, chair storage, AV booth, reception desk, lift, island tables, and stairwells. Main entrance is at the bottom left near the Piazza entrance.
Floor plan of a large hall with 30 tables arranged classroom style, located near the piazza entrance. The hall includes an altar, a section with a carpet, and a stage area for a drum booth. To the left are stairs to underground, an AV booth, and a reception desk, with stairwells and storage rooms at the far left and right. The floor plan is labeled 'The Great Hall'.

Event Floor Plans for Conferences and Corporate Days

Our floor plans are designed to inspire and help you visualise your event layout at St Mary’s. Every corporate event, conference, or business gathering is unique, and we work closely with you to customise the setup to suit your needs.

Please note: trestle tables are included with venue hire, while round tables will need to be arranged separately.