A gay couple in the US state of Colorado has filed a discrimination lawsuit against a bakery, saying it refused to provide a cake for their wedding, and alleging a history of discrimination against same-sex couples.

The complaint was filed against Jack Phillips, after the couple David Mullins and Charlie Craig, visited the Masterpiece Cakeshop in Colorado in 2012.

The couple said Mr Phillips said he would not make a cake for them, after he found out they were celebrating their wedding in Colorado, after they got married in Massachusetts.

He said making a wedding cake for a gay couple would violate his Christian beliefs, read the complaint.

The Colorado Attorney General’s office last week filed a formal complaint, following the American Civil Liberties Union (ACLU), which initated the process in 2012.

Mark Silverstein, the legal director of the ACLU in Colorado said: “We are all entitled to our religious beliefs and we fight for that… But someone’s personal religious beliefs don’t justify breaking the law by discriminating against others in the public sphere.”

The ACLU said it had discovered that two other gay couples had been refused wedding cakes from Masterpiece.

Mr Phillips’ lawyer Nicole Martin said: “At its heart, this is a case about conscience. I just don’t think that we should heighten one person’s beliefs over and above another person’s beliefs.”

The discrimination complaint hopes to make the bakery “cease and desist” the practice of refusing service to couples based on their sexual orientation, and to publicly declare that their business is open to everyone.

