There is a museum in Britain dedicated to telling the story of a same-sex couple who met, eloped and commenced 50 years of 'married' life together more than 200 years ago.

Miles from any major urban conurbation, Plas Newydd, Llangollen (North Wales), recounts the remarkable lives of the couple, Lady Eleanor Butler and Sarah Ponsonby, who became known as the Ladies of Llangollen.

However, if it were possible to take a snapshot of every display in every other museum in Britain on the first day of Lesbian, Gay, Bisexual and Transgender (LGBT) History Month, how many do you think would contain material relating to LGBT people and be identified appropriately as such?

And, crucially, how many of those would still have such material on display five weeks later? I would hazard a guess that less than half of 1 per cent of British museums could currently make that claim.

In other words, LGBT people are completely invisible in 99.5 per cent of the country's permanent exhibitions. Their lived experiences, their cultures, their contributions to the world, their art and the persecution they have faced all fall outside these institutions' interpretative frames of reference.

That is not to say that some material on display is not queer, through ownership, authorship, usage or other provenance - merely that either the interpretative framework leaves no space for that to be integrated into the public narrative, or the museum's documentation, or lack of it, prevents staff from even being aware of any potential connection.

No one knows how many museum objects are LGBT-related, or whether staff are aware of such connections, or even (with limited notable exceptions such as the Museum of London) if they have taken this on board as an issue that needs to be addressed.

And that is why the Proud Nation Survey was launched in December. The aim of the survey is to catalogue what is held and where, and to forge a network of relationships that could lead to change (the survey is included on the leaflet enclosed with this month's Museums Journal).

But this is just a first step. Proud Heritage's goal is to create a museum, at first online and then in physical reality. There are unique challenges and complexities underlying the cultural politics of LGBT representation and we are committed to transparent decision-making and to including LGBT people in the collecting, interpretative and framing processes. Our aim is to develop innovative good practice with partners across the sector, and beyond.

Wherever LGBT people live LGBT history also lives. That some people experience same-gender love and desire, or seek ways to shift or subvert gender identity, is as much part of the human condition as variations in eye colour or being left- or right-handed. It has ever been thus.

Of course, in different cultural or societal settings, in different places and at different times, men and women experiencing such feelings - together with their families and wider society - have understood themselves and others like them in many and varied ways.

The language these individuals have used to describe themselves and their desires has changed with time, as have the ways people expressed, sublimated or repressed such drives. They have also been on the receiving end of prejudice, stigma and discrimination - or in some cases affirmation and support. In some cultures and at different times in history, they may even have been accorded elevated status.

As LGBT people, our heritage and history is not transmitted through the family, by parents and grandparents passing on personal and collective memory to children. The reality is that many LGBT people in Britain have little idea whose shoulders they stand upon.

There is no settled narrative describing the diversity of our experience, locally, nationally, collectively. Proud Heritage is working alongside others to piece this together.

Thankfully, there is still a living historical archive among us: men and women who recall life from the 40s onwards; people who have lived in cities, towns and villages across this country. For the most part that lived experience goes unrecorded and artefacts remain uncollected. But for how long is that tenable?

It is easy enough to understand how museums sector came to exclude the queer experience; decriminalisation happened less than 40 years ago; Section 28 was perceived, often wrongly, as a bar on such work. But what needs to be done to move forward?

It is time to integrate an LGBT dimension into all museum cultural diversity programmes, and that includes black and disabled LGBT experience. It is time the Heritage Lottery Fund; the Museums, Libraries and Archives Council; and the Department for Culture, Media and Sport made targeted funds available to redress this historic imbalance.

And individual institutions, large and small, should make public their desire to put right past injustice and eradicate unwitting institutional homophobia. Now that would be a project worth launching in LGBT History Month - or indeed at any time.

Jack Gilbert is the executive director of Proud Heritage

www.proudheritage.org