The Muslim boy who was arrested when his teacher mistook a homemade clock for a bomb has demanded $15m (£10m) in compensation.

Lawyers for Ahmed Mohamed, the Texan pupil known as 'clock boy,' have warned that if the local mayor and the school did not apologise and pay the compensation, they would file a civil action.

Two letters sent by the Laney and Bollinger law firm said the incident, which made global headlines and sparked threats against the 14-year-old, had left him with "severe psychological trauma."

"Irving Police officials immediately determined that the clock was harmless," the lawyers wrote in a letter to the City of Irving.

"The only reason for the overreaction was that the responsible adults involved irrationally assumed that Ahmed was dangerous because of his race, national origin and religion.

"Ahmed never threatened anyone, never caused harm to anyone, and never intended to," the letter continued. "The only one who was hurt that day was Ahmed, and the damages he suffered were not because of oversight or incompetence."

The arrest sparked an outcry and thousands expressed their support and sympathy with the trending hashtag #StandWithAhmed.

After the arrest was sharply criticised Ahmed was invited to the White House where he attended a science evening and met President Obama.

His father is a Sudanese immigrant to the US and in October Ahmed was invited to met the Sudanese President Omar al-Bashir in the Sudanese capital of Khartoum. His father had once stood as a presidential candidate against Bashir.

Subsequently he met the Google co-founder Sergey Brin and officials from Turkey, Sudan and Jordan.

Since the arrest the family have revealed they moved to Qatar after the Qatar Foundation for Education, Science and Community offered Ahmed a full scholarship.