A British Israeli academic has told the BBC of his shock at being detained by Israeli police for wearing a Jewish kippah, or head covering, embroidered with an Israeli and a Palestinian flag.

Alex Sinclair, 53, said he was taken from the café where he was sitting near his home in Modiin, central Israel, on Monday, ordered to hand over his kippah and locked in a cell. When the item was returned to him, the part with the Palestinian flag had been cut off.

The unusual case has gained domestic and international attention after Sinclair shared the details in a social media post. Police told the BBC a complaint has been filed with their internal investigations division.

Sinclair, who is also a novelist, was working on his laptop in the café when, he said, 'a religious man came over to me with an angry face and shouted at me that my kippah is against the law'.

He said he invited the man to sit down to discuss his views, but he refused and said he would call the police. 'Five minutes later, the police arrive,' he wrote on Facebook. 'Two officers, and they immediately tell me that my kippah is against the law and that they are going to confiscate it.'

Sinclair said he tried to explain 'politely' that his kippah was not illegal but was taken into detention and driven by police car to the police station. He said he was forced to hand over his possessions and unable to make a phone call. Sinclair said he was then frisked and locked in a cell.

Twenty minutes later, Sinclair said, he was told he could leave but without his kippah. He said when he insisted on it being given back, the officer handed it to him with the Palestinian flag cut out. Sinclair called the incident 'surreal'.

'That photo of the ripped kippah – there's something so kind of evocative about it,' he reflected. 'I think that's part of the reason that this story has gone so crazy.'

Israeli police stated that officers had attended the scene to 'assess and address' a report on a hotline about a man wearing a kippah with a Palestinian flag. A complaint has been filed with the Police Internal Investigations Division following Sinclair's release.

Sinclair regularly wore his kippah with the Israeli and Palestinian flags on a black background over the past 20 years. He described it as a symbol of 'the messy ambivalence of my Jewish-Zionist identity.'

He expressed his desire to promote coexistence, stating, 'I'm doing all of this as a Zionist, as somebody who chooses to live here, as somebody who believes in the right of Israel to exist and to flourish in security, along with the Palestinians having those same rights as well.'

This occurrence sparks debate on freedom of expression, as there is no explicit law against public displays of the Palestinian flag in Israel; however, police may act if they interpret it as posing a threat to public order.

In response to the incident, Sinclair plans to order a new kippah featuring both flags, asserting that it may start a new trend in expressing dual identities.