Men across England and Wales will be able to apply to have criminal convictions given for consensual gay sex scrapped from today (1 October).
Stonewall, Britian's leading gay campaign organization, lobbyed for the axing of laws that criminalized gay sex as part of the Protection of Freedoms Act 2012.
Stonewall chief executive Ben Summerskill said: 'Thousands of men who've been burdened with homophobic convictions can clear their names and Stonewall stands ready to help them.
'We never forget that the equality we enjoy today came too late for many.'
After laws were changed, many men were left with convictions and cautions such as gross indecency and buggery on their criminal records.
This left them feeling unable to apply for jobs as they feared their convictions could be revealed.
Men can have their convictions disregarded if two key conditions are satisfied, these being if the consensual person was 16-plus and if the sexual activity was not carried out in a public toilet, which is still illegal.
The act also includes amendments enabling gay and bisexual men maliciously convicted of 'loitering with intent' under Section 4 of the Vagrancy Act 1824 to have those convictions removed too.
Summerskill added: 'By correcting these historic injustices we can start to bring closure to a very sad period of this country's history.'
A form to have the offences disregarded can be downloaded from Stonewall's site and today the charity will publish a step-by-step guide to help applicants exercise their new rights.