A survivor of the 7/7 London bombings whose bloodied face became one of the best known images of the day could face expulsion from the UK.

John Tulloch lost his British nationality under a clause governing people born in pre-independence India. Despite being raised and educated in the UK from the age of three and working and living in the country for most of his life, Tulloch's status as someone born to British parents in the former colony led to him losing his nationality when he took out Australian citizenship.

"I am totally gobsmacked by this," said Tulloch, who has been told that he can only visit Britain for brief periods as a tourist. "I've got a huge attachment to Britain. My family has served Britain for three generations. I've been banging my head against a wall trying to get this sorted out, but I've never before encountered so much frustration. It's like Kafka."

The army officer's son was granted a lesser form of British nationality known as "British subject without citizenship".

Following a career in UK academia, he was granted citizenship in Australia after taking a job there. Tulloch returned to the UK after directing the Centre for Cultural Research into Risk between 2002 and 2004 at Australia's Charles Stuart University. Prior to that, he was head of the School of Journalism at Cardiff University. Unlike "full" British citizens, who could hold dual citizenship, Tulloch's acquired Australian status led to the cancellation of his British nationality and his passport was confiscated when he applied for its renewal.

"Neither I nor my parents ever received information from the government that this was somehow an inferior passport," Tulloch told the Sunday Telegraph. "In particular, the passport itself explicitly said that you could take out dual nationality without risking your British nationality."

Tulloch, who was around a metre from bomber Mohammad Sidique Khan at Edgware Road tube station in the 7/7 attacks, said: "There I was, hailed as an example of British courage, British pluck and the British spirit, an iconic image of British resistance. I get blown up in the media as a British patriot, then I get kicked out."

He added: "When I came back from a trip to Vienna two or three months ago, I got a really hard time at Heathrow. I am worried that if I leave again, I might not be let back in." A UK Border Agency spokesman said: "If you are a British subject otherwise than by connection with the Republic of Ireland or a British protected person you will lose that status on acquiring any other nationality or citizenship. It is the responsibility of an individual to check that they will not lose a previously acquired nationality or citizenship on acquiring an additional one."

However, Home Office sources said that Tulloch would be "welcome to submit" an application to extend his stay in the UK in an appropriate category."