Labour MP Stella Creasy has called on the prime minister to challenge the US after a UK Muslim family was barred from boarding a flight to Los Angeles.
The family of 11, from Ms Creasy’s Walthamstow constituency, had planned a holiday to Disneyland but were stopped at Gatwick Airport on 15 December.
Mohammad Zahid Mahmood said his family was given no reason why US officials had refused to allow them to board.
US officials said travellers were not barred based on religious beliefs.
Downing Street said David Cameron would respond to the issues raised.
Ms Creasy has written to the prime minister urging him to press the US authorities on what she said was “a growing problem” of British Muslims being barred from the US without explanation.
She said she had “hit a brick wall” in her own attempts to get answers from the US embassy.
“It is not just the family themselves who are livid,” Ms Creasy told the Guardian. “The vacuum created by a refusal to provide any context for these decisions is fuelling resentment and debate,” she said.
She told BBC radio 5 live she was aware of four other UK cases of Muslims who were denied entry to the US.
“Nobody knows why these people were stopped. We do know what the common denominator is between them. All of us agree we’ve absolutely got to be vigilant about tackling terrorism, and we’ve got to be clear prejudice hasn’t got a part to play in that,” she added.
Mr Mahmood, who was travelling with his brother and their children, aged eight to 19, had planned to visit their elder brother in southern California and go to the theme parks.
He said UK Border officials told them at the departure lounge that they were not allowed to board the plane, despite all having authorisation to travel under the US Visa Waiver Programme.