Tim Farron has issued a challenge to Theresa May to publish a report focusing on Saudi fundings
Mr Farron said that the Prime Minister must be ready to have “difficult and embarrassing conversations” with the Gulf kingdom, to which the UK recently approved arms export licences worth £3.5 billion.
In the wake of Saturday's terror attack at London Bridge, Mr Farron also accused Mrs May of making the wrong choices on security, reducing police funding while handing billions to business in corporation tax cuts.
And he dismissed the Prime Minister's call for tighter regulation of the internet as “posturing”, arguing that she should instead be working with online giants to develop methods for keeping people safe while maintaining free speech.
Mrs May's predecessor David Cameron agreed to an inquiry into foreign funding of Islamist extremists in 2015 as part of a deal with Liberal Democrats in return for their support on the extension of air strikes into Syria.
Farron claims the PM must be ready to have “difficult and embarrassing conversations”
Reports last week suggested that the report may never be published because of the sensitivity of its findings about Saudi Arabia, though the Home Office said a decision on its release would be made after the election.
Mr Farron said: “When we lent our support to the government for extending air strikes against so-called Islamic State in Syria, one of the Liberal Democrats' key demands was a report into foreign funding of extremism here in Britain.
“The then Prime Minister, David Cameron agreed to that demand. Theresa May now has a choice. Does she publish that report, or keep it hidden?
London terror raids Sun, June 4, 2017
Police have raided a block of flats in Barking in connection with last night's London Bridge terror attack.
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As police continue their investigations following the June 3 terror attacks, a block of flats in Barking is raided for possible suspects
“Theresa May talks of the need to have some difficult and sometimes embarrassing conversations. That should include exposing and rooting out the source funding of terror, even if it means difficult and embarrassing conversations with those like Saudi Arabia that the Government claims are our allies.”
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In a broadside against Mrs May's record on security as Home Secretary and Prime Minister, Mr Farron added: “In the choice between cuts to corporation tax and properly funding our police, we should fund our police.
“Let's be clear: fewer police on the beat means fewer conversations, less information being passed on and less knowledge about who's who and who needs to be kept under surveillance.“
Defending his opposition to powers for bulk data collection by the state, Mr Farron said: “Instead of posturing, politicians need to work with technology companies like Facebook, Twitter and WhatsApp, and with other countries, to develop solutions that work to keep people safe.
“The alternative is a government that monitors and controls the internet in the way that China or North Korea does. If we turn the internet into a tool for censorship and surveillance, the terrorists will have won. We won't make ourselves safer by making ourselves less free.”
He added: “In the choices we make, we should provide the resources necessary for those who keep us safe to do their jobs with the powers they have been given. We should also jealously guard the hard-won liberties that define us as a country. If we make the wrong choices, those who seek to change our way of life have won.”