The Court of Appeal has dismissed a challenge over the legality of random stop-and-search powers aimed at tackling street violence.

The Metropolitan Police has been accused by Ann Juliette Roberts of breaching human rights laws by using the controversial powers against a disproportionately high number of black Londoners.

Mrs Roberts, 39, of Upper Edmonton, north London, claimed that the powers allowing ''searches without justification'' were discriminatory on the grounds of race and incompatible with the European Convention on Human Rights.

She applied for a judicial review but two High Court judges ruled the police had acted lawfully and section 60 of the 1994 Criminal Justice and Public Order Act did not breach human rights.

Today, Lord Justice Maurice Kay, Lady Justice Rafferty and Lady Justice Macur rejected her claim that the High Court had gone wrong in law.

Mrs Roberts became involved in a row with police in September 2010 after a ticket inspector discovered there were insufficient funds on her Oyster to pay her fare after she boarded a number 149 bus.

According to the police, she lied about her details and was uncooperative and behaved in a suspicious manner.

A police officer called to the scene thought she might be concealing a knife in her bag and she was subjected to a search under section 60.

She was arrested after obstructing the search and handcuffed but had to be taken to the ground when she continued to resist.

No weapons were found and Mrs Roberts, who was of good character, received a caution which was later quashed.

The police had been authorised to use section 60 powers, which allow ''random'' searches, in the Haringey area because of gangland violence involving the use of weapons.

Mrs Roberts, a black woman with an African-Caribbean heritage, sought declarations that section 60 is incompatible with Articles Five and Eight of the human rights convention, which protect the right to liberty and private life.

She also wanted a declaration that the section violates Article 14, which prohibits discrimination on the grounds of race or colour.

Lord Justice Maurice Kay said the scheme of section 60 could not be said to be arbitrary as it permitted the use of stop-and-search powers only for a very limited period of time - up to 24 hours, extendable by a maximum of a further 24 hours.

"Its temporal limitation is accompanied by a territorial limitation. The authorisation must relate to a 'locality' within a police area.

"Accordingly, there is no question of a 'rolling programme' across the whole area covered by a police authority. It is based on local intelligence of a specific kind, namely serious violence involving weapons."

He added: "In summary, I am entirely satisfied that section 60 does not provide an arbitrary power. It is 'in accordance with the law'. It is circumscribed by specific requirements so that, notwithstanding its exceptional nature, it is justified pursuant to Article 8(2)."

Turning to Article 14, he said it was appropriate to stand back and take stock in the circumstances of the case.

"It is not suggested, nor could it be, that section 60 is intrinsically discriminatory. Nor is it suggested that the grounds for authorisation were not established.

"It is true that the area covered by the authorisation has a sizeable proportion of black residents - although `residence' is not directly relevant to authorisation or use of the stop-and-search power.

"However, the assumed facts of this case demonstrate that Mrs Roberts was not subjected to section 60 because of her ethnicity. She drew attention to herself as a fare dodger at a time and in a place where a section 60 authorisation was in place in accordance with the statutory requirements.

"I am sensitive to the fact that the use of stop-and-search powers, including those under section 60, attract criticism, particularly among some ethnic minority communities in London. That is a proper subject for debate elsewhere.

"However, it does not have the potential to render justiciable a specific allegation of discrimination in this particular case. I am wholly unpersuaded that a breach of article 14 has been established."

Mrs Roberts was not in court for the ruling.

James Welch, legal director for Liberty, said later: "The argument for stop and search without suspicion has been lost time and again - in our communities, courtrooms and classrooms.

"We're decades overdue in scrapping these counterproductive, discriminatory powers. Since the court failed to recognise this, it may take Strasbourg to see sense."