It was heard that because some Christians would be prepared to work on a Sunday, Christians as a whole do not need Sunday protected.
Mr Justice Langstaff issued the judgment as he ruled on an appeal brought by a Christian woman who was fired after she refused to work on Sundays at a care home.
Celestina Mba claimed that it was agreed that she would not have to work on Sundays in accordance with her Christian beliefs; however the Council changed the arrangement after she commenced her employment, saying that the arrangement was only temporary.
Miss Mba said she found herself constantly allocated Sunday shifts and threatened with disciplinary measures unless she agreed to compromise her church commitments, meaning she had no alternative but to resign from the job she loved, she said.
The care worker launched an unsuccessful legal claim in February 2012 and recently lost her appeal in the High Court.
Mr Justice Langstaff upheld the lower tribunal’s ruling which said it was relevant that other Christians did not ask for Sundays off.
The fact that some Christians were prepared to work on Sundays meant it was not protected, the court said.
The senior judge said that a rule imposed by an employer which affected nearly every Christian would have a greater discriminatory impact than one which only affected a few.
He added that there was evidence that many Christians work on Sundays and this was relevant in “weighing” the impact of the employers’ rule, and the earlier decision did not involve an error of law.
Yvette Stanley of Merton Council, Miss Mba’s former employers, said it did its best to allow religious practice but also had a duty to meet the needs of the disabled children for whom it cares.
“We are pleased with the outcome of this second tribunal. Staff recruited in the respite care service are advised that it is by its nature a weekend service.”