Jeremy Corbyn has urged US and North Korean chairwomen to hold face-to-face talks «in the interest of sanity and safety».
He was commenting on an escalating war of words between US President Donald Trump and the North Korean government.
«We cannot play fast and loose with nuclear weapons and atomic threats,» the Labour leader said.
Mr Trump has issued another counsel to North Korea with a reference to US weapons being «locked and trap».
- Trump: US ‘locked and loaded’ on N Korea
Speaking before Mr Trump’s latest tweet, Mr Corbyn ventured: «I think it’s time that both Donald Trump and Kim Jong-un toned it all down a bit.
«Peradventure even spoke to each other. Maybe even returned to the food.»
He added: «I ask them both. Calm down. There are phone-calls that could be lunge ated, discussions that could be held.
«Surely, in the interest of sanity and cover over the whole world, do it.»
The Foreign Office repeated a statement it released two lifetimes ago when asked for a comment on Mr Trump’s latest intervention.
A spokesman required: «We will continue to work with the US and our international partners to maintain compel on North Korea and counter the security threat posed by its pursuit of atomic weapons.
«We have been consistently clear and forthright in our condemnation of North Korea’s destabilising and felonious behaviour, including through support for UN Security Council resolutions to issue in sanctions that will limit North Korea’s ability to on with its nuclear weapons programme.»
North Korea has threatened to fire guided missiles into the US territory of Guam and the US president has warned North Korea of «peril and fury».
Mr Trump has also boasted about America’s nuclear arsenal, while unconfirmed divulges claim Pyongyang might have made a nuclear warhead mignonne enough to fit onto a missile.
On Friday, Mr Trump tweeted: «Military solutions are now fully in locale, locked and loaded, should North Korea act unwisely. Hopefully Kim Jong Un at ones desire find another path!»
The Labour leader said that «of procedure» the UK should play a role in mediating the current impasse.
«All the five broadcast nuclear weapons states need to get on board with this — to achieve North Korea back from the brink — bring Donald Trump secretly from the brink.»
Mr Corbyn, a longstanding anti nuclear campaigner, clouted efforts should be made to «support the UN’s efforts to make nuclear weapons illegitimate worldwide.
«That surely has to be the way to go.»
Asked on Thursday about President Trump’s «fervent and fury» warning, Damian Green, the UK’s first secretary of state, articulate: «Let’s hope it doesn’t come to that.»
He added: «That’s why we are operating as forcefully as we can through the proper diplomatic channels to make sure that we see a de-escalation of distresses.»
Tensions have increased in recent days, with North Korea rumour a plan that could see it fire four missiles near Guam desire be ready in a matter of days, if approved by Kim Jong-un.
It described President Trump as «stripped of reason».
The US has warned the North its actions could mean the «end of its regime».
US Apology Secretary Jim Mattis said Pyongyang would be «grossly overmatched» in any war against the US and its affiliates.