I'm depressed. There's no other term for it. I've just sat through two hours of the Liberal Democrats' diversity debate that sought to address the fact that they, as elected politicians at Westminister, the Greater London authority, the Welsh assembly, the Scottish parliament and the European parliament, are all white, with very few women, and none have disabilities. And yet they voted to do nothing. They decided to throw out every practical measure aimed at addressing the structural inequality that has persisted for the last 50 years.

The former councillor Charles Anglin summed up the fundamental problem within the party when he informed conference that he was told by the local party chair of a target seat that he didn't win the nomination because he was "too urban". The party's only deaf councillor, David Buxton, implored the conference to recognise the inequalities within the party for people of disability and minority ethnic communities and demanded positive action. His pleas held no sway.

Instead, speaker after speaker passionately reminded the conference that any intervention, including having black and minority ethnic (BME) candidates on shortlists for target seats, or having a programme to recruit more BME members, was discriminatory and therefore illiberal. In spite of being told that the colour-blind approach would simply maintain the status quo, that well meaning but misguided thinking prevailed.

What was particularly depressing about this debate is that we've been here before. Many times before. It usually occurs every five years, or when a new leader takes the helm. In 1997 Paddy Ashdown showcased some 30 BME candidates for that election, proclaiming that, although it was unlikely any would be elected, the next election would be the breakthrough. Similar noises were made by Charles Kennedy and Menzies Campbell and as recently as last year, Nick Clegg stated that if the Lib Dems remained all white after the election he would consider it a failure.

Actually the real failure is within the party leadership. Having promised to prioritise the issue, other than Simon Hughes – who made an impassioned speech in favour of the motion – the leadership were nowhere to be seen.

Ultimately, today's decision will not help the party become more appealing to minority ethnic communities. Under the Cameron project the Conservatives realised that a 21st-century party had to be more inclusive and representative. They also realised that to make the breakthrough strong leadership would have to convince the party that change needed to happen, and where necessary they would use positive-action measures such as the A list, or persuading Tory grandees to mentor brilliant candidates. Their efforts made history. They went from a miserable two BME politicians to a respectable 12, the largest increase at one time by any political party.

The Liberal Democrat bosses face many challenges in the weeks and months ahead, not least implementing coalition cuts at a rate that would normally have their rank and file manning the barricades in opposition. But they must not ignore the inequality within their own party. Confronting their internal problems of representation will also aid in bringing in a new generation of supporters, who will see that this isn't a party that just talks the talk when it comes to diversity, but walks the walk too.