This morning I left the castle for the first time in almost a week after a nasty infection kept me in bed for several days. Feeling better and keen to get out I went to meet one of my oldest friends, Anna, and her four year old daughter Neva. I was also introduced to her very new and very cute son Koah who’s only a few months old.

We met at Dulwich Picture Gallery which isn’t far from either of us. I was keen to see their latest exhibit, The Colour Palace, a striking summer pavilion by the designer Yinka Ilori and architects Pricegore.

I’d looked online in advance to try and check how wheelchair accessible it was but I couldn’t find any specific information on the website. Reassured by the gallery’s general access page, which said ‘All areas of the Gallery are on one level’, I agreed with Anna to meet there as the Palace looked incredible and would be great for the kids too.

My support worker Chris and I arrived first and Anna and her family soon joined us. We headed straight to the Colour Palace which was stunning – it filled the gardens with bright, bold colours and shapes. Neva was excited to explore the structure and I was too, but sadly the raised viewing area that runs around the inside of the structure is only accessible by stairs.

Photo by Edward Bishop

This was a big disappointment, which I felt in three distinct ways:

Firstly, I was upset not to be able to experience a key element of the work just because I’m a wheelchair user.

Secondly, I was sad not to be able to explore this piece of art with Neva – I feel exclusion even more keenly when it impacts on my friends and family, particularly on children.

Finally, I felt frustrated that yet again disabled people were expected to accept a second rate experience. This was a new structure, built from scratch and designed by a team who are obviously extremely talented and creative and yet the decision had been made not to include an accessible viewing platform!

From my understanding of our equality legislation, service providers – including galleries and cultural spaces –have an obligation to ensure that disabled people are not treated ‘less favourably than others’. If they are, this is direct discrimination.

By creating an installation that I could look at only from the ground and not explore and view from ‘many different perspectives’, as the team behind it promise, I’m surely getting a worse version of this piece of art.

Nowhere did I see any mention of this limited access, either online or at the gallery. There were no ‘reasonable adjustments’ that might’ve helped compensate for the lack of access – like photos of the view or binoculars to see the higher levels of the structure up close.

While I would expect the design team to have thought about access and been aware of their legal and ethical responsibilities, ultimately it’s the gallery and commissioning organisations that I hold accountable. Access had clearly not been an integral element of the brief – and I’d really like to know why not.

We’re all constantly being sent messages by our surroundings, and the message I got very clearly from the Colour Palace was ‘This isn’t for you’.

This installation is far from the only offender – last week Tate Modern hit the headlines after writer and wheelchair user Ciara O’Connor was unable to experience a sculptural installation by Olafur Eliasson because of two steps and no ramp. And Jeremy Deller’s recent memorial to the Peterloo massacre in Manchester faced fierce criticism from disabled activists because he’d created a speakers’ platform that could only be accessed by steps (Although there are plans to address this following a campaign by disabled people.)

Why does Dulwich Picture Gallery think it’s ok to have a large-scale exhibit that’s not equally accessible to everyone? I’d guess that a few of the following assumptions might be at play:

• ‘Only a few people will be affected’ – The belief that access is a niche issue affecting only a handful of people is totally wrong: one person in five in the UK identifies as disabled. While they may not all be wheelchair users or have mobility impairments, a great many will. The Gallery is also used by young families so a ramp would also have made this sculpture accessible to buggies and family groups too.

• ‘You can still look at and enjoy the art from the ground’ – The idea that disabled people should be grateful for whatever access they’ve been given is unacceptable and disingenuous. If you can enjoy the piece equally well from a distance why let non-disabled people get closer up?

• ‘It’s just this one exhibit’ – This misses the point and the reality of disabled people’s lived experience of cultural spaces. Exclusion is at its most pernicious when it has a cumulative impact. This is far from the only piece of non-accessible art, and time after time disabled people are expected to ‘go round’, ‘ just look’ or ‘make do’.

• ‘It’s the artists choice’ or ‘we don’t want to compromise the aesthetic’ – It’s puzzling to me that teams of supposedly creative people can suddenly lack imagination when it comes to access. Access itself can be beautiful, elegant or seamless and I passionately believe that if you make art inclusive you make it better, richer and more effective.

• ‘No-one else bothers’ – The legislation in this area is weak in that it relies on disabled people having a rubbish time and then taking legal action. It’s not regulated and enforced in any active way and I think this makes businesses complacent about their legal duties. I expect our cultural spaces, particularly those that benefit directly from public money, to ensure that, at the very minimum, they are meeting their legal duties.

My questions for Dulwich Picture Gallery are:

1) What impact assessment has been undertaken to understand how many people will be excluded from this piece?

2) Why was it judged to be acceptable for disabled people to have a less comprehensive experience?

3) What action will you take to prevent other people from being disappointed in the way we all were today?

4) Will you commit to no new barriers by ensuring that accessibility is an essential element of all future project briefs?

5) What measures are you taking to ensure that you meet your obligations under the Equality Act 2010?

6) What commitments are you making to reflect disability culture within your programme?

I really hope the gallery will answer these questions quickly and honestly. If needed, as a disabled-led organisation that works across art forms, Touretteshero is well placed to offer support and advice.

The true impact of bad access is often invisible to non-disabled people. For example on-going issues with pain and energy mean that I have about three hours of energy a day so in order to make the visit this morning I had changed my care arrangements, visited the gallery website, paid for a taxi, and taken extra medication. Rather than using my remaining energy to explore the sculpture with Neva and Koah, I had to expend time and emotional energy explaining why we couldn’t get up the stairs.

I’m not expecting artists and designers to know everything about access all at once, but I am asking them to expect their audience to include disabled people and their families. We deserve to experience their work fully and equally.

I’m calling on galleries to step up and ramp up, to audio describe, caption and relax – it’s no longer acceptable for access to be an afterthought.

The work we share and how we share it says a lot about our collective values. If we’re going to build a rich, responsive, and socially just cultural sector to inspire new audiences and artists, it’s time to make sure everyone gets written in. Putting accessibility at the heart of all creative briefs is a good place to begin.

Artists can control the art they make but they don’t get to dictate who sees it.

Update: I’ve been in touch with Dulwich Picture Gallery and the web page for the Colour Palace has now been updated to include access information.