Britain should “open its heart” and take in 3,000 child refugees living alone and unaccompanied by their parents in Europe, Tim Farron has said.

The Liberal Democrat leader will this week propose a Private Members Bill that would commit the UK to taking in Syrian, Iraqi, Afghan and Eritrean children displaced by conflict and living alone in Europe.

Unknown thousands of children have entered Europe unaccompanied in the past year. The UNHCR estimates 8,500 arrived in Italy alone between January and October. The Save the Children charity that if the country were to take its fair share of refugee children, Britain should find homes for 3,000.

The proposed Bill, which will be considered by MPs on Tuesday, is the latest bid by opposition parties to make the moral case to Government for greater action over the refugee and migrant crisis which has seen hundreds of thousands arriving in Europe from the Middle East and North Africa this year alone.

Labour, the Liberal Democrats and the SNP are also seeking to change the law to allow asylum seekers already in the UK to bring elderly relatives, children over the age of 18, and in some cases siblings into the country.

While the UK is a leading donor of aid to refugees in Syria and in camps in neighbouring countries, it has faced criticism for its modest offer of taking in 20,000 refugees by 2020.

“These children have left their home fleeing terror and persecution. I believe Britain must, as it always has done, offer safe haven and open its hearts to those in desperate need," Mr Farron said.

"I am urging the government to support my bill and establish a programme to take in 3,000 unaccompanied children who are currently alone in Europe.”

The call is backed by Save the Children, which has urged people not to “harden hearts” against refugees in the wake of mounting fear over the threat of terrorism in the wake of the Paris attacks, which have led to calls by some for tightening of border controls and a tougher stance on immigration and asylum.

Justin Forsyth, the charity’s chief executive, said last week that Britain should be inspired by the example set by the ‘kindertransport’, which saw 10,000 Jewish children come to the UK from Nazi Germany before the Second World War.