A 14-year-old Sikh girl excluded from school after refusing to remove a religious bracelet was a victim of unlawful discrimination, a High Court judge ruled yesterday.

Sarika Singh, from Cwmbach, south Wales, was excluded by Aberdare Girls' School in November 2007 for breaking a "no jewellery" rule and refusing to take off the Kara, a religious bangle.

But yesterday Mr Justice Stephen Silber said the school failed to promote equality in banning the teenager from class, declaring the school was guilty of indirect discrimination under race relations and equality laws.

"In this case there is very clear evidence it was not a piece of jewellery but to Sarika it was, and remains, one of the defining focal symbols of being a Sikh," he said.

As a result of the decision, the teenager can return to the school as its only Sikh in September - wearing the Kara.

Mr Justice Silber hoped the school would take "all possible steps to ensure that (she) can become quickly assimilated again within the school and that there will be no bullying of her for racial or religious reasons."

He refused the school permission to appeal, although it can still seek permission from the Court of Appeal.

Aberdare Girls' School has said the thin steel bangle breaks its rules, which only allow watchbands and plain ear studs.

The comprehensive has said it "self-funded" its defence of the case, because Rhondda Cynon Taf County Borough Council, the education authority, decided not to support the school. It would not comment on where the money came from.

Sarika's lawyers told Mr Justice Silber that the Kara bracelet, a symbol of her Sikh faith, was as important to her as it was to England bowler Monty Panesar, who has been pictured wearing the bangle.

Sarika, who is of Welsh and Punjabi origin, was at first taught in isolation and was later excluded for refusing to take off the bangle in defiance of the school's policy.

On the court steps, Sarika said: "I am overwhelmed by the outcome I just want to say that I am a proud Welsh and Punjabi Sikh girl. I would like to thank all of the people who have helped me with this, especially my mum and dad."

The case was the latest to test whether pupils can wear religious clothes or symbols in school.

After yesterday's decision, Anna Fairclough, legal officer for Liberty, the civil liberties organisation, who represented the Singhs, said: "This judgment makes clear you must have a very good reason before interfering with someone's religious freedom."

A spokesman for Rhondda Cynon Taf council said it would "be working with the school's governing body to ensure Sarika Singh's continued education".