Sikh teenager Sarika Watkins-Singh this week won support from her new headteacher as her discrimination claims against her old school reached the High Court.

Mick Guilfoyle, head of Mountain Ash Comprehensive School in Mid Glamorgan, said he did not have a problem with her wearing the kara. He said it was just “a small bangle”.

Miss Watkins-Singh was excluded from Aberdare Comprehensive Girls’ School in Rhondda Cynon Taff last November after refusing to take off the steel wristband, one of the five Ks of the Sikh faith.

She has been at Mountain Ash since February after three months of home tuition. She challenged her exclusion this week at the High Court.

But her mother said her daughter’s wish, if triumphant in court, was to return to her old school.

Sanita Singh, 38, said her daughter’s education had suffered. “Sarika is having a really hard time,” she said. “She was comfortable there with her friends and teachers and it’s all been turned upside down. The trust between teacher and pupil was broken when she was put into isolation for nine weeks.”

The schoolgirl’s lawyers this week told Mr Justice Silber that Miss Watkins-Singh had been a victim of unlawful discrimination at a school that allowed no exceptions on cultural or religious grounds.

The judge heard that the steel wristband meant as much to Ms Watkins-Singh as it did to England spin bowler Monty Panesar. But the school’s code of conduct on uniform did not permit jewellery other than wristwatches and plain ear studs.

Helen Mountfield, for Ms Watkins-Singh, said the issue was whether the school’s policy amounted to unlawful discrimination, and whether there had been breaches of the freedom of religion provisions of the 2006 Equality Act and the 1998 Human Rights Act.

The school also launched its defence this week.

Jonathan Auburn, barrister for Aberdare Girls’, said the school was “prepared to recognise exceptions”, although he stressed the “need for clarity in the rules”.

The school was well aware of the need for flexibility and was now considering “drawing up a list of items” that might escape the ban, said Mr Auburn, who added that those proposals would depend on the High Court’s decision.

It was altogether wrong to say that the school was “blind to exceptions”, he said, adding that “no doubt the school has learnt from this experience”.

“The bar as to what’s acceptable may be higher in some schools than in others. For Aberdare, it was clearly a matter of principle,” said Mr Guilfoyle who has Miss Watkins-Singh on his school roll temporarily.

The Assembly government issued new guidelines on uniform in January following the case. These state that governing bodies should consider policies within the context of race equality, and that a body could be regarded as discriminating if it did not address religious needs concerning dress.

While the Assembly government “does not consider exclusion to be an appropriate response to breaches of uniform policies, the school may consider exclusion as a last resort depending on the circumstances”, the guidelines said. But some education professionals say the guidelines remain unclear.

As TES Cymru went to press, the case was expected to adjourn the judgement to a later date.