Equality is “at the heart of the coalition government” and vital to building a modern economy, home secretary Theresa May told employers today.

“Now, more than ever, we need to make sure we are using the talents and the skills of every person in this country,” said May, who is also minister for women and equalities. “So equality is not an optional extra that we should only care about when money is plentiful – it’s central to our task of building an economy fit for the 21st century.”

May said that one in five lesbian, gay and bisexual (LGB) employees had experienced bullying from their work colleagues because of their sexual orientation.

The government was aiming to “reclaim the equalities agenda”, but the whole of society had a part to play, the delegates in London heard.

“Government can act as a leader, a convenor and an advocate for change,” said May. “But on its own it will only ever make limited progress. We need to work with people, communities and businesses.”

May held up the government’s new Public Sector Equality Duty as an example of its new approach.

“Public bodies will now need to consider the needs of LGB people when designing their services, and internally in their own staff practices,” she explained. “We want to empower organisations to move away from the tick box and form filling of the past, and instead to encourage all organisations to take responsibility for their own performance and to be held to account by the public.”

May also called on the private sector to act. “Many organisations now recognise that equality at work not only makes moral sense, but it also makes good business sense,” she said. “Inclusive and diverse companies and public services benefit from the fresh perspectives, new ideas and broad experience that a diverse workforce can bring.

“An organisation which is open and welcoming to all kinds of people will attract the best talent,” she added. “And a company that better reflects its customers is more able to understand its customers’ needs.”

In her speech, May also announced that schools would receive “authoritative guidance” to deal with bullying, the ban on civil partnerships being held on religious premises would be repealed, and that gay men could apply to have convictions disregarded for actions that would not be considered an offence today.