The BBC has been told to do more to help the 2 million people who are colour blind in the UK after the BBC Trust upheld a series of complaints about confusing general election graphics.

Kathryn Albany-Ward, founder of Colour Blind Awareness, described some of the corporation’s election coverage as a “fiasco” and accused the BBC of trying to “brush off” her complaints.

She raised a number of concerns about the BBC’s graphics around last year’s general election, including the use of least nine different shades of orange and white text on a yellow background which was “unreadable”.

The BBC Trust upheld six out of seven complaints brought by the not-for-profit community interest group, and said BBC management had “failed to meet best practice standards and … had not considered the needs of a significant majority of its audience at an important time”.

“We have been making the BBC aware for some time that a lot of their broadcast and online information is difficult for colour blind people to understand – with virtually no success,” said Albany-Ward.

“When the impending 2015 election graphics fiasco came to our attention and we were being given the brush-off, we decided enough was enough. The BBC can’t stand by and knowingly discriminate against nearly 5% of the population at any time, but in the run-up to a general election we found their attitude to be totally unacceptable.

“We decided to make an example and despite constantly being ignored all the way through the very lengthy BBC complaints procedure we have finally been vindicated by the BBC Trust complaints and appeals board which upheld six out of seven of the points we made.”

Colour Blind Awareness commended presenter Jeremy Vine, the figurehead of the BBC’s election graphics, but said a number of difficulties were caused by the on-screen colour palette.

Jeremy Vine fronts BBC coverage of the 2014 European elections Photograph: BBC

It said colour blind people had difficulties distinguishing between the Conservatives’ blue and Ukip’s purple, between Labour’s red and the Lib Dems’ orange, and between Lib Dem orange and SNP yellow.

The BBC, in response, said it used official party colours and was “constrained in that regard”.

The corporation said it used a number of systems to double check the graphics were colour blind friendly, including software packages called Snook and Vischeck. It also ran a training session on the issue for online designers.

In its findings the trust “asked the BBC to review the totality of its guidance for people with colour vision deficiencies, across broadcast and online”.

It “concluded that the BBC had failed to meet best-practice standards and in so doing it had not considered the needs of a significant minority of its audience at an important time”.

A BBC spokesman said: “The BBC leads the industry in making accessible programmes and we strive to produce graphics that are clear and informative for all viewers.

“During last year’s election coverage we used text labelling and journalist explanations, both online and on television, to convey graphical findings in other ways.

“Whilst we are restricted to using official political party colours we have already made many changes to our graphics, partly in response to our conversations with Colour Blind Awareness, including the use of party logos and adjusting some colours and how we contrast them on graphics.”

Colour Blind Awareness was set up by Albany-Ward in 2009 as a non-profit organisation because of colour blindness in her family. One in 12 men and one in 200 women in the UK are colour blind, around 4.5% of the population.

Albany-Ward added: “Unfortunately, many BBC graphics are still inaccessible and we are looking forward to finding out how and when the BBC intend to implement the changes recommended by the trust. We hope that in their new role [media regulator] Ofcom will be monitoring the situation closely.

“We also hope the new culture secretary, Karen Bradley, will be willing to meet with us discuss how colour blind people can also be afforded proper access to sport and to digital information.”