Labour Mayor hopeful Sadiq Khan warned that Londoners were 'being left vulnerable' by the government's failure to stop radicalisation and extremism amongst some British Muslims.

The MP for Tooting said the threat of home-grown terrorism was "the biggest security threat facing Londoners today" and not enough has been done to tackle the issue .

Labour ’s mayoral candidate called for the government to completely overhaul the anti-extremism programme Prevent, after criticising the scheme for not working.

The programme has been repeatedly criticised by Mr Khan and Home Secretary Theresa May for not working.

Last year, a 15 year old boy from Blackburn was sentenced to life imprisonment for his involvement in the Anzac Day terror plot in Australia despite being on the government’s de-radicalisation programme.

This followed the case of Brusthom Ziamani, who was found guilty of plotting to behead a British soldier despite being on the Prevent programme at the time.

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Mr Khan said: “The increase in radicalisation and extremism is the biggest security threat facing Londoners today.

"In the aftermath of the terrible Paris attacks we should be under no illusion that London is a target for the extremists.

“The government must act to get extremist websites taken down, promote greater social integration and support mainstream Muslims to speak out against the extremists.

“Most urgently, they must reform the anti-extremism programmes so that they actually work to keep Londoners safe.

"For too long this government have identified the problem but done nothing to fix it."

'More armed police crucial'

MP for Richmond Zac Goldsmith, Conservative mayoral candidate highlighted Mr Khan's failures to highlight the importance of armed officers on patrol.

He told getwestlondon: “I've made it clear that we need to tackle the root causes of crime in our community - and that includes tackling the root causes of homegrown terrorism - including the preachers of hate who groom vulnerable young people, and the organisations like Cage which give them a platform.

"But now more than ever, we also need to stand up for the police who keep us safe.

"That’s why I’m standing for the doubling of armed officers on patrol - something Sadiq Khan has failed to do."

Downing Street were approached for comment, but were unable to respond.