Jeremy Corbyn today sought to point the finger of blame at Tory budget cuts and the invasion of Iraq in the wake of the London Bridge terror attack.
Streamlined public services will 'miss chances to intervene in the lives of people who go on to commit inexcusable acts,' the Labour leader said today.
Mr Corbyn also took aim aim at his Labour predecessor Tony Blair, saying that the 2003 invasion of Iraq 'set off a spiral of conflict' that fuelled terrorism.
In his speech in York, Mr Corbyn insisted that 'I will always do whatever is necessary and effective to keep our people safe.'
However, a poll which was published last night revealed that only 24 per cent believe Mr Corbyn is the best candidate to defend Britain from attack, compared to 54 per cent for Mr Johnson.
It comes amid a furious political row over how London Bridge terrorist Usman Khan was able to walk free from a previous terror conviction and slaughter two people in a knife rampage on Friday.
Warning: Labour leader Jeremy Corbyn (pctured in York today) is today seeking to blame Tory budget cuts and the invasion of Iraq for the London Bridge terror attack
Khan was released from prison last year after his initial 'indeterminate' prison term was changed to a fixed sentence by the Court of Appeal in 2013.
Home Secretary Priti Patel yesterday blamed legislation brought in by Labour in 2008 for guaranteeing that Khan would be released after half of that sentence.
But with just 11 days until the general election, Mr Corbyn is today seeking to shift the blame to the spending axe wielded by the Conservatives after coming to power in 2010.
'It is our duty to look calmly and seriously at what we need to do to give people real security,' the Labour leader said.
'Our public services are the glue that bind our society together. Community policing, the probation service, mental health, youth and social services, all play a vital part.
'When those public services are cut back as they have been during the past decade, they leave behind gaps.
'That can lead to missed chances to intervene in the lives of people who go on to commit inexcusable acts, whether it's during their childhood, their first brush with the law, their first conviction, or in prison through rehabilitation programmes.
'Real security doesn't only come from strong laws and intelligence, it comes also from effective public services that have the funding they need. You can't keep people safe on the cheap.'
Emergency: Police surround London Bridge terrorist Usman Khan moments before shooting him dead after he killed two people in a knife rampage on Friday
Blaming the invasion of Iraq for fuelling terrorism, Mr Corbyn says: 'For far too long, our country's leaders have made the wrong calls on our security.
'Their mistakes in no way absolve terrorists of blame for their murderous actions. The blame lies with the terrorists, their funders and recruiters.
'But if we are to protect people we must be honest about what threatens our security. The threat of