All couples in Scotland should be able to choose civil partnerships, rather than getting married, campaigners have claimed, after a court ruled that denying them to opposite-sex couples was discriminatory.

The Humanist Society for Scotland (HSS) has urged the Scottish Government to act after a ruling that allowing only same-sex couples to have civil partnerships was incompatible with equality law.

The decision in the Supreme Court was a defeat for the UK Government, but Scottish law also denies civil partnerships to people who are not in a same sex relationship.

Read more: Heterosexual couple take civil partnership fight to UK’s highest court

The Scottish Government said in February that it would review the future of civil partnerships "in due course".

But the Supreme Court found in favour of the appeal of Rebecca Steinfeld, 37, and Charles Keidan, 42, of Hammersmith, West London, who argued civil partnerships were discriminatory because only same-sex couples are eligible.

Five supreme court justices granted a declaration that the 2004 Act was "incompatible" with human rights laws on discrimination and right to a private and family life.

HSS has led a campaign to have civil partnerships available to all couples and as part of their campaign to see same-sex marriage legalised, the society called for civil partnerships to be redefined so they are open to opposite-sex couples.

Gordon MacRae, Chief Executive of HSS said: "The Scottish Government must now take swift action to change the law in regard to this finding and avoid further procrastination. This will allows all couples to choose the special day – marriage or civil partnership – that means the most to them.

"At HSS we campaigned for same sex marriage and we were proud that it was one of our celebrants who performed the first same sex marriage at the bells struck on Hogmanay 2014.

"But we know that for some, marriage is still associated with traditional for women and men or has religious connotations unsuited to many couples. For same sex couples they can choose a meaningful civil partnership. For opposite sex couples there is no alternative."

Read more: Row as ministers refuse civil partnerships to straight couples

During the Supreme Court hearing the London couple's barrister Karon Monaghan QC said their action was not frivolous and said they had "deep-rooted and genuine ideological objections to marriage" which she said was "historically heteronormative and patriarchal."

The Government said it was decided against extending civil partnerships to opposite-sex couples, intending instead to see how extending marriage to same-sex couples impacted on civil partnerships before making a final decision.

Lord Kerr, announcing the court's decision, said the Government "does not seek to justify the difference in treatment between same-sex and different sex couples". He added:"To the contrary, it accepts that the difference cannot be justified."

However the court was told the UK government sought "tolerance of the discrimination while it sorts out how to deal with it". Lord Kerr said: "That cannot be characterised as a legitimate aim."