A powerful army of nearly 100 MPs have joined the growing backlash against British Airways over its decision to ban check-in worker Nadia Eweida from wearing a cross necklace.
Customers taking BA's routes to America and Africa have vowed to use other airlines in protest.
Miss Eweida's case is also being cited as an example of religious oppression at a top-level United Nations conference.
Christian student leaders, who are caught up in a row over their right to declare their faith in Jesus at universities, claim that Miss Eweida had fallen victim to the same "secular fundamentalism" that has targeted their own activities.
The University and Colleges Christian Fellowship, national umbrella body for the Christian groups, said BA's ban was "ridiculous".
A staggering total of 92 MPs - one seventh of the House Commons - from all parties have signed parliamentary motions condemning BA's "deplorable" ban of Miss Eweida's tiny cross.
The list includes serving and former Cabinet Ministers, as well as one Muslim and one Hindu MP. Some have joined Ministers Peter Hain and Ben Bradshaw in threatening to boycott the airline over its "intransigence".
They added their weight to the Archbishop of York Dr John Sentamu's criticism that BA's policy was "nonsense" and was ignoring Britain's cultural heritage.
Miss Eweida, 55, lost her appeal to wear her cross with her uniform to work at Heathrow on Monday. She has been off work for two months over the row.
The 55-year-old had appealed against the decision, saying that she should be entitled to openly proclaim her Christian faith.
"In seven years I have not had any complaints from passengers about my cross being visible," Eweida told Sky News.
Eweida told reporters that she was effectively "forced" to take unpaid leave after refusing to hide the symbol.
During Monday's meeting, British Airways explained that it respected her faith and accepted the cross was not jewellery, but would stand firm on its original decision.
BA, however, denied it had banned the wearing of crosses and said Eweida had a right to a second appeal. The company has come under heavy criticism from leaders of other faiths but has said its uniform policy stated that such items could be worn if concealed underneath the uniform.
Conservative MP David Davies said: "It is absolutely disgraceful that BA have done this. Members of Parliament are frequently contacted by BA to try and encourage us to travel with them.
"I will be writing to the Commons authorities asking them whether MPs should choose an alternative airline in future."
Labour MP and deputy leadership contender Jon Cruddas said: "I think BA's behaviour is ridiculous and I support her case. It seems to me totally ridiculous that she should be banned from wearing a religious symbol."
Liberal Democrat MP Tim Farron, parliamentary aide to Sir Menzies Campbell, said: "People have a right to wear religious symbols and to be told otherwise is distinctly un-British.
"The whole debate on religious symbols has got out of hand. We are a tolerant nation and this behaviour from BA seems to be extremely intolerant indeed."
