Parents who suspect their children are heading for violent jihad abroad must inform the police because having them in prison is still better than being dead, a senior counter terrorism officer said.
Detective Chief Superintendent Sue Southern, head of the West Midlands Counter Terrorism Unit, said it was too late to help families once their loved ones had already left the country.
She delivered the stark message at Birmingham Central Mosque wearing a hijab – the first time a counter terrorism chief has worn the Muslim headscarf while making a national public statement.
The appearance at the mosque came two weeks after the Government demanded schools actively promote British values as part of a sweeping plan to stamp out extremism following the alleged Trojan Horse plot.
Ofsted issued a damning verdict on a number of schools in Birmingham at the centre of the plot to install hardline Islamist practices in the classroom.
The meeting at the mosque was arranged amid growing concern over the number of young British Muslims who are being lured to Syria and Iraq to fight alongside terrorists and fanatics.
However, one imam warned the Government to stop trying to “infiltrate” Islam or “funding ideas to try and change Islam from inside”.
Up to 500 Britons are feared to be fighting in Syria and Iraq, many with the terror group Islamic State of Iraq and al-Sham (Isis).
DCS Southern said: “We need parents to become more vigilant, to learn about what their children are doing online and talk to them about it.
“We need to be able to stop these people before they go, knowing they are there afterwards means we can’t do anything.
“It does not always mean that person going to prison, but in the end perhaps being in prison is better than being dead.”
Imam Sheikh Muhammed Ismail Al-Rashid, from Birmingham Central Mosque, said: “I praise the good work done by West Midlands Police, they are always working with the community at the roots.
“But I call on the government to change its ways. Stop funding ideas to try and change Islam from inside. Work with us, ask us, do not try and infiltrate us.
“It is the role of the Imams, the parents the families to talk to their children, not the politicians to try and change us.”
But Shaykh Arif Abdul Hussain, founder of the Al-Mahdi Institute in Birmingham, said: “This is not the ideology of a Muslim, the fight is not about Muslims, no one should be there fighting.
“To say this is jihad and a part of Islam is an embarrassment for us, the people who follow this interpretation of the holy Koran are wrong.”
A West Midlands Police spokeswoman said: “As a courtesy, all female police officers and staff wear head scarves when visiting mosques.
“DCS Southern has made many such visits during her career with West Midlands Police and has always chosen to respect the custom.
“All the female journalists covering this morning’s event wore a head covering. As guests it was simply good manners to do so.”
In the House of Commons, Hazel Blears, the former counter terror minister said work to stop young people being radicalised in British communities must be reviewed because fighters returning from Iraq and Syria are “ready to attack” at home.
And General Lord Richards, the former chief of the defence staff, warned the imminent withdrawal of international forces from Afghanistan could see the country fall in to the kids of conflict now being witnessed in Syria and Iraq.