Hussen Abase, father of 15-year-old Amira, one of three girls who travelled secretly from London last month to join Islamic State in Syria, is a quietly-spoken man, unused to the corridors of power.

Nearing the end of his appearance before the House of Commons's home affairs committee, Labour MP Keith Vaz asked him if he had any advice to offer parents who fear that one of their children might try to make the same journey.

Shoulders hunched, clutching a walking-stick, the 47-year-old Hussen Abase, who looks older than his years, replied disconsolately: “Simply I would be say be vigilant, not to fall into the same trap.”

Hussen Abase, however, has questions, not answers. A friend of his daughter's who went to the same school in east London, the Bethnal Green Academy, travelled to Syria in December, prompting an investigation by the Metropolitan Police. Seven girls in the school were questioned by officers, including his daughter.

Counter-terrorism letter

However, they were told not to speak to others but, instead, given a letter to hand on to their families: “The letter terrified my daughter,” Abase believes.

“The letter shouldn’t have been given to a 15-year-old: a letter about counter-terrorism. To deal with that is a heavy burden for a 15-year-old. We are supposed to know these things,” Abase said

Meanwhile, Bethnal Academy had equally been told by counter-terrorism police not to tell anyone – including the parents of its pupils – that one of its students had travelled to Syria.

The letters were not passed on by his daughter or by Shamima Begum (15), or their friend Kadiza Sultana (16), who all flew to Istanbul last month. Instead, the families heard only that a girl in the school "had gone missing".

Once the alarm was raised, the families complain the Metropolitan Police did not act quickly enough – especially now it has emerged that the girls waited for nearly 18 hours at a bus station in Istanbul.

“We were told that police were on the ground looking for them,” said Sahima Begum, older sister of Shamima Begum, “We kept asking . . . and we were told, ‘Yes, we do, yes we do.’ We were told their photos had been circulated. But the girls were in the bus station.”

Alarm raised

By contrast, family solicitor Tasnime Akunjee told MPs of a previous case where the alarm was raised when a young Muslim from London was still on a flight to

Turkey

. Then, security officials were present at Istanbul airport before he landed and sent him back: “It appears that the families were not taken seriously.”

Relations between the three families and police are poor, and worsened by the decision to appoint an officer they blame for not alerting them as a liaison officer. The officer believes, said Akunjee, that Bethnal Academy was responsible for ensuring the warning letters were passed on to the families of the seven girls questioned. The school, in turn, says it gave him the addresses when requested to do so.

Later, Akunjee complained the same officer had called one of the families and told them “not to listen to me” – not realising that the solicitor was sitting in the same room as them when the call came through.

Minutes after they had finished giving evidence, the Metropolitan Commissioner, Sir Bernard Hogan-Howe, read from a prepared statement, apologising that the letter had not reached them.

“First of all we’re sorry if the family feel like that, clearly it’s a terrible situation they find themselves in, having lost their daughters in such a horrible way. You can only half imagine what a parent is going through at this time.Also sorry the letter we intended to get through, didn’t get through . . . It was intended for them and failed and for that of course we’re sorry.”