evidence: The Democratic Unionist Party is the largest of Northern Ireland’s four major parties, and one of two unionist parties – meaning parties which favour a continued political union with the rest of the UK. [...] The party insists it is not ‘anti-gay’ but opposes gay marriage equality and has worked to block the legalisation of same-sex marriage in Northern Ireland using peace process powers called ‘petition of concern’. The petition needs the signatures of 30 members to block legislation and the DUP had 38 members until March 2017. Northern Ireland’s assembly voted for same-sex marriage in 2015. However, the DUP used this process to block any change in legislation. [...] Gregory Campbell, East Londonderry: He said that the DUP would not be the "Northern Ireland branch of the Conservative Party, adding: "We have voted for them when they have done the right thing and we have voted against them when they haven’t. He said that they would negotiate strong and hard for the Tories to "deliver for Northern Ireland." He stoked controversy last year after joking about dead IRA men, Gibratar and the Celtic Football Club. He refused to apologise. He also supports bringing back the death penalty for mass murder.