A Labour MP has called on the Prime Minister to challenge the US after officials refused to allow a Muslim family permission to board a flight to the country from Gatwick.
Stella Creasy has written to David Cameron urging him to press American authorities on what she says is a growing problem of British Muslims being barred from the US without explanation.
The family of 11, from Ms Creasy's Walthamstow constituency in north east London, had planned a holiday to Disneyland in California, saving thousands of pounds for the trip.
But as they went to board the Norwegian Airlines flight to Los Angeles from the Sussex airport on December 15 they were approached by officials from the US Department of Homeland Security, who told them their authorisation to travel had been cancelled.
The father, Mohammad Tariq Mahmood, said no reason was given as to why they could not board the flight, even though the family were allowed to under the Visa Waiver programme, which authorises travel to the US for up to 90 days without a visa.
Mr Mahmood, who was travelling with his brother and nine of their children, told the Guardian he believed the reason was "because of the attacks on America - they think every Muslim poses a threat".
Ms Creasy said she is concerned about increasing numbers of British Muslims being stopped from entering the US with no apparent reason.
Writing in the newspaper, she said she had "hit a brick wall" with getting an explanation from American authorities and so has asked Mr Cameron to intervene.
Ms Creasy said: "The vacuum created by a refusal to provide any context for these decisions is fuelling resentment and debate.
"Online and offline discussions reverberate with the growing fear that UK Muslims are being 'trumped' - that widespread condemnation of Donald Trump's call for no Muslim to be allowed into America contrasts with what is going on in practice."
She added: "Just a week ago, parliamentarians were united in agreement that Trump's views were abhorrent. Now we should do more than shrug our shoulders at secretive American security policies that leave our constituents in such limbo.
"If the embassy won't answer to the family's MP, it should answer to their prime minister and he to us about what he is doing to ensure that no British citizen is being discriminated against for their faith on our shores."
Downing Street said Mr Cameron would respond to the issues raised by Ms Creasy.