A Christian B&B landlady who was ordered to compensate a gay couple after refusing them a double bed is to fight her case in the highest court in the land.

Susanne Wilkinson refused to let Michael Black, 62, and John Morgan, 56, who are not civil partners, share a bed in her Swiss B&B, in Terry's Lane, Cookham, in March 2010.

Staunchly religious Mrs Wilkinson, a married mother-of-four, believes that sex before marriage is a sin and "against God's law" and says she refuses to let unmarried couples - whether straight or gay - share a bed under her roof.

However a judge at Reading County Court ruled last year that she had unlawfully discriminated against the gay couple on grounds of their sexual orientation and awarded Mr Black and Mr Morgan, who live in Brampton, Cambs, damages of £1,800 each.

As the gay marriage debate rages in Parliament, the Court of Appeal today dismissed Mrs Wilkinson's appeal against that ruling. However, in an extremely rare move, she was granted permission to argue her case before the Supreme Court.

Her case will be heard by Supreme Court judges in October at the same time as that of Peter and Hazelmary Bull who were famously found to have discriminated against gay partners, Steven Preddy and Martyn Hall, at their Chymorvah Hotel, in Marazion, Cornwall.

Mrs Wilkinson, who says she will have to shut her business if forced to allow unmarried couples to sleep in the same bed, insists she is in no way anti-gay and that her "old fashioned" beliefs on sex before marriage have not been afforded the respect they deserve.

Her counsel, Sarah Crowther, earlier told the Appeal Court: "It is not any part of her case to undermine the rights of Mr Black and Mr Morgan. She believes that homosexual or heterosexual sexual relations outside marriage are wrong and against God's law.

"The embarrassment and humiliation that Mr Black and Mr Morgan felt on that occasion is undeniable. However that is something that reasonably robust individuals would get over in time. To require Mrs Wilkinson to close down her business is irreversible and permanent.

"She is not in the business of refusing rooms to homosexual individuals - what she will not do is supply double rooms to unmarried couples."

However, Henrietta Hill, for Mr Black and Mr Morgan, told the court: "The reason they were treated less favourably is that they were two men and they were two gay men. That is the beginning and end of it.

"The requirement that the couple must be married is necessarily linked to heterosexual orientation. There is no homosexual couple, whether in a civil partnership or not, who could be married".

The barrister said the only way that Mrs Wilkinson and her husband could lawfully avoid the obligation to offer all their accommodation to any guest would be to re-open as a Christian retreat rather than an ordinary B&B.

Granting Susanne Wilkinson permission to argue her case before the Supreme Court, the Master of the Rolls, Lord Dyson, said her case raised 'difficult and controversial questions of moral judgment' that needed to be resolved once and for all.

He rejected the landlady's plea that being ordered to compensate Michael Black and John Morgan amounted to a violation of her own human right to practise her religion and refuse double beds to unmarried couples - whether straight or gay.

The judge, sitting with Lady Justice Arden and Lord Justice McCombe, said that he was 'bound' and 'constrained' by the law to 'reluctantly' find that Mrs Wilkinson had directly discriminated against the gay couple.

She had also indirectly discriminated against them on grounds of their sexual orientation in that, at least at present, no gay couple can ever be 'married' and her policy therefore disadvantaged Mr Black and Mr Morgan when compared to heterosexual couples.

The landlady's bar on having unmarried couples share a double room at her three-bedroom establishment could not be viewed as a 'proportionate means' of fulfilling her genuine and legitimate religious beliefs, the judge ruled.

Mrs Wilkinson's bed&breakfast was 'essentially a commercial rather than a religious enterprise' and, although it was 'possible' she might have to shut her business due to the court's decision, that could not justify what she had done.

The court heard Mr Black emailed Mrs Wilkinson to book the room and paid a £30 deposit. However, when he and Mr Morgan arrived, she told them 'there was a problem as they had booked a double room'.

The couple say they were embarrassed and humiliated when Mrs Wilkinson told them 'she did not like the idea of two men sharing a bed' and refunded the deposit before they left.

However, Mrs Wilkinson says she would have been happy to let the couple sleep in separate rooms, had they been available, and would have reacted in exactly the same way if confronted by an unmarried heterosexual couple.