Policing minister Nick Herbert, Britain’s most senior out gay politician, will attend Europe’s largest Pride celebration in Warsaw tomorrow, where he is expected to encourage Tory allies to be more tolerant.

Prime minister David Cameron said in April that Mr Herbert, then the shadow environment minister, would attend the event.

Mr Cameron said the gay minister would help the other conservative European parties to embark on a “journey” of tolerance towards gay rights.

Last year, the Tory party left its EPP grouping in the European Parliament to join the European Conservatives and Reformists Group, which includes the Polish Law and Justice Party.

A number of the Polish party’s senior politicians have made homophobic statements, with the late president Lech Kaczynski banning Pride marches.

In the last year, the Conservative Party has undergone a a conversion in favour of gay rights. Mr Cameron apologised for Section 28 last summer and has made a number of promises to the LGBT community, including tackling homophobic bullying and striking out historic gay sex convictions.

Mr Herbert said in a statement today that he hoped the Tories’ conversion would inspire other political parties.

He said: “I know that in some countries social attitudes are evolving more slowly.

“We ourselves have further to go to ensure equality in the UK. I also believe that part of living in a tolerant society is to show respect for the proper exercise of individual conscience and religious belief.

“But I hope that when others see how the Conservative Party has changed under David Cameron’s leadership, reaching out to people and communities which we couldn’t reach before, they will be encouraged to take the same course.”

He added: “I wanted to take part in EuroPride to support the event and send an unequivocal message that the British Conservative Party has changed, that we’re committed to equality, and that an agenda to ensure respect and equality for gay people is completely compatible with modern conservatism.

“Under David Cameron’s leadership, we have developed a modern, progressive agenda, with a commitment to equality and a determination to ensure that no one in today’s society should be discriminated against because of their gender, race, or sexuality.”

Earlier this month, Mr Herbert spoke at London Pride, where he said the coalition government still had a “huge agenda” to move forward on equality.