Sir Vince Cable will say today that following the nerve agent attack earlier this month, Britain will be safer from similar attacks in the future if it is part of the bloc.
The Lib Dem leader, who is calling for a second Brexit referendum, will claim leaving the EU during such an unpredictable period in global geopolitics would be “utter folly”, with the UK facing the threat of war with Russia, a trade war with the United States and the ever-growing influence of China.
He will use a speech at a Brexit conference to criticise the Government’s “amateur” handling of the divorce and refusal to change its position despite forecasts the country will inevitably be worse off after the split.
And he will say because the world is becoming a “very dangerous place”, the British public will be safer if the UK shows solidarity with its European neighbours instead of going it alone.
Former double agent Sergei Skripal and his daughter Yulia were poisoned with a military-grade nerve agent in Salisbury on March 4.
Theresa May has said tests revealed the Soviet-era chemical weapon was produced in Russia, adding it was “highly likely” Moscow was behind the attack.
The Prime Minister has since announced a series of tough measures in retaliation, including the expulsion of 23 Russian diplomats from the UK.
Moscow continues to deny any involvement and responded to Mrs May’s actions by ordering British diplomats out of Russia.
At the Should I Stay Or Should I Go conference in London today, Liberal Democrat leader Sir Vince will say: “The world is becoming a very dangerous place and for Britain to be leaving the EU at this time is utter folly.
“Within the past fortnight we have seen acts of aggression by Russia and, with that, the need for solidarity with European allies.”
Germany, France, the United States and Nato have all already expressed their support for the UK following the nerve agent attack and condemned the Kremlin for its alleged role.
The former Secretary of State for Business, Innovation and Skills will also make the case for stopping Brexit by claiming the UK could be “frozen out” of European and international markets if President Donald Trump follows through on his threats of trade wars.
The US leader recently announced hefty tariffs on imported steel and aluminium as a way to revitalise America’s declining metal industries and put an end what he has branded as “unfair” trade practices by the likes of China and the EU.
However EU officials have signalled Mr Trump is willing to make exemptions to the duties if member states agree to assist him in his trade war against Beijing.
On the prospect of a trade war with the US, Sir Vince will say: “We have seen Trump embarking on trade warfare and economic nationalism.
“Britain now risks being frozen out of both a genuinely free trading European market and the rest of the world characterised by rising trade barriers.
“We have seen a much less benign China starting to emerge with little interest in cultivating Theresa May’s ‘global Britain’.”
And in an attack on the Theresa May’s handling of the Brexit process, the Lib Dem is expected to compare the Government to an ill-prepared, amateur mountain climber.
He will say: “The British government is behaving like an amateur climber deciding that, having planned to go off hiking in the mountains, they will not change their plans despite the fact that there are blizzards on the way and there isn’t a map or compass or the necessary clothing available.”