Business · 4 min read · Updated 6 November 2026
Corporate marquee events: CDM, risk assessments and Martyn's Law
Why corporate events are different
A private couple booking a garden marquee is a domestic client, so most legal duties sit with the hire company. When a business, school, charity or venue books a marquee for a launch, staff party, hospitality event or exhibition, it takes on duties of its own. HSE guidance confirms that building and dismantling temporary structures at events can count as construction work under CDM 2015, whatever the scale.
In practice, most of the work is done by the marquee company, but the client still needs to play its part by choosing a competent supplier, sharing information and allowing enough time for the build.
CDM 2015 roles in plain English
| Role | Who it usually is | Key duty |
|---|---|---|
| Client | The business, organiser or venue booking the marquee | Check the contractor is competent and provide site information |
| Contractor | The marquee company | Plan, manage and carry out the build safely |
| Designer | The marquee manufacturer or supplier | Design the structure to resist expected loads |
| Principal designer and principal contractor | Only on projects with more than one contractor | Coordinate planning and the build phase |
Many corporate events have several contractors on site, such as staging, lighting, catering and power. In that case the client must appoint a principal designer and principal contractor, and on a typical event the organiser or production company often takes these roles.
Information to share with the supplier
- A site plan with the marquee position, access route and nearby buildings
- Underground services such as drains, cables and pipes
- Overhead cables and trees
- Ground conditions or hard standing details
- Timings for the build, event and take-down
- Other contractors working at the same time
- Expected guest numbers and how the space will be used
- Fire safety arrangements and emergency access
The more of this you share early, the more accurate the risk assessment and quote will be, and the fewer changes are needed on the day.
Documents to expect from the supplier
- Risk assessment and method statement for the build and take-down
- Structural calculations or a design statement for the marquee
- Flame retardancy information for the fabrics
- Wind management plan, including action levels
- Public liability insurance details
- A completion or handover certificate once the marquee is built
Licensing authorities and safety advisory groups may ask for some of these for public events, so ask for them early.
Managing the build on a working site
Corporate marquee builds often happen on working sites, such as car parks, office grounds, hotels or schools, where staff, visitors and vehicles are still moving around. Keep the build area fenced or clearly marked, agree times for deliveries, and keep pedestrians away from moving vehicles and lifting. Brief your own staff on where they can and cannot go until handover.
If the build overlaps with business hours, think about noise and disruption for staff and neighbours, such as hammering stakes or reversing alarms early in the morning. Agree working hours with the supplier, and tell building management, security and reception what is happening so they can direct visitors and deliveries.
A planning timeline for corporate events
| When | What to sort |
|---|---|
| 3 to 6 months before | Book the supplier, confirm the site and guest numbers, start any council or landowner approvals |
| 2 to 3 months before | Site visit, agree layout, power, heating and catering areas |
| 4 to 6 weeks before | Receive risk assessments, method statements and insurance details |
| 2 weeks before | Confirm build timings, access, parking and contractor schedule |
| Build days | Keep the area controlled, coordinate other contractors |
| Before guests arrive | Receive the handover certificate and walk the site |
Larger public events often need longer, as some councils ask for applications several months ahead. Starting early also gives time to fix anything the supplier spots at the site visit, such as underground services or access problems.
Martyn's Law and larger events
The Terrorism (Protection of Premises) Act 2025, known as Martyn's Law, received Royal Assent in April 2025. Once in force, qualifying public events where 800 or more people are expected at the same time will need enhanced measures, such as security plans, staff training and procedures. The implementation period is expected to be at least 24 months, and the Home Office is publishing guidance during that time.
Most corporate marquee events are private and much smaller, but large festivals, shows and public hospitality events should start planning now.
Frequently asked questions
Does CDM apply to a small marquee at a business event?
It can. HSE guidance says construction work covers work of any scale and complexity, and building temporary structures at events can fall within CDM 2015. For a small, single-contractor job the duties are proportionate: check the supplier is competent, share relevant site information, allow enough time, and cooperate during the build and take-down.
What is a marquee handover certificate?
It is a document from the supplier confirming the marquee has been built, anchored and checked in line with its design, and is ready for use. Event organisers, venues and safety advisory groups often ask for it before guests are allowed in. Keep it with your event records.
Does Martyn's Law apply to our staff party?
Martyn's Law is aimed at publicly accessible premises and events. A private staff party is unlikely to be a qualifying event, and qualifying events need 800 or more people at once. Large public events should follow Home Office guidance as it is published, as the duties are expected to come into force after an implementation period.
corporate events CDM 2015 risk assessment Martyn's Law
Related services
We cover 250 towns and cities, including Bath, Birmingham, Coventry, Nottingham, Mansfield, Manchester.
