Designed by British artist and lesbian, gay, bisexual and transgender (LGBT+) activist Holmes, the honorary coin features the words protest, visibility, unity and equality in capital letters on colourful rainbows.
The word pride is embossed in capital letters in the middle of the coin underneath an engraved heart and swirling lines, referencing the movement that celebrates and campaigns for the rights of the LGBT+ community.
"My aim with this design was to evoke images of the original Pride marches – the hand-made placards and protest signs calling out the demands of the brave LGBT+ people who were taking to the streets to fight for their rights," Holmes told Dezeen.
The seven-sided coin's eye-catching rainbows are coloured in the same hues as seen on the Rainbow Flag, which was designed by artist Gilbert Baker in 1978 and is widely recognised as the symbol of LGBT+ communities.
On the bottom of the coin, which will not be circulated as currency, is an arrow coloured in shades of black, brown, pink, light blue and white stripes.
These colours were added to the Rainbow Flag by graphic designer Daniel Quasar to represent LGBT+ individuals of colour and transgender individuals, in an effort to emphasise "inclusion and progression". Quasar's Progress Pride Flag has since become routinely used around the world.
"When the first Pride March took place in the United Kingdom, LGBT+ people were forced to live their lives on the margins of society, often in secret," Pride in London told Dezeen.
"It may have taken 50 years to get here, but we are now a country which not only recognises the fundamental human rights of LGBT+ people but celebrates them via one of the most accessible links between our state and its people – our currency."
The first UK Pride event took place 50 years ago in London in 1972. The march was a protest in solidarity with those involved in the Stonewall Riots in New York – a series of riots that began in response to a police raid of the Stonewall Inn.
The coin marks the first time Britain's LGBT+ community has been celebrated on official UK coinage. As part of the coin's launch, the Royal Mint will make a donation to Pride in London.
"Each year the Royal Mint commemorates key moments, events and individuals from British history," the Royal Mint told Dezeen.
"The 50th anniversary of London Pride is an important cultural milestone which has helped shape modern Britain and we are proud to honour the landmark LGBTQ+ event on a UK 50 pence."
The coin will be available in special edition gold and silver from The Royal Mint's website in the summer.
The Royal Mint has commemorated other British figures and movements of significance on its coins including a 50p coin that references black holes to honour professor Stephen Hawking.
To celebrate the 150th anniversary of London Underground, the organisation commissioned British studio BarberOsgerby to design a new £2 coin.