The Liberal Democrats have become the first mainstream party to back the legalisation of cannabis after voting at their spring conference in York. The Lib Dems put the vote to the crowd attending the York Barbican, with just a handful of members voting against the motion.

The radical stance from the party, who were embarrassingly trounced in last years' general election, could be a way to appeal to the younger voter which Lib Dems have failed to win back since the university fees debacle.

The motion is the first major policy change in Tim Farron's tenure as party leader and follows a report produced by the party which said that regulated shops and cafes could generate up to £1bn ($1.42bn) in taxes for the Treasury.

The report, entitled A Framework For A Regulated Market For Cannabis In The UK, argued for a number of measures suggesting that cannabis should be sold to over 18s in licensed shops and it should be regulated around the price, potency and packaging. In another suggestion cannabis could go on sale over the counter in pharmacies with clear health and risk reduction information.

Liberal Democrat health spokesperson Norman Lamb said: "This is a groundbreaking report that is a huge contribution to the debate on introducing a regulated cannabis market in the UK. Every year, billions of pounds are put into the pockets of organised criminals selling cannabis, and vast amounts of police time and resources are wasted, going after those using the drug.

"We have to be ambitious. It is not good enough to continue pretending that everything is OK, or that the current system is working. Millions of British citizens are using cannabis with no idea of the potency of what they are taking.

"The current system is doing untold harm: on health grounds and on justice grounds. Leaving the cannabis market in the hands of criminals puts people's health at risk, and criminalises people, blighting their careers. Meanwhile, how many members of the government have taken cannabis and got away with it?"

Lamb has spoken in the past about his son Archie's battle with drink and drugs. The long-serving member for North Norfolk lost to Tim Farron in the Liberal Democrat leadership contest in 2015. Lamb mourned last May when the yellows saw 48 of their MPs wiped out at the general election and Nick Clegg stepping down as party leader.

The 57-year-old, one of just eight Liberal Democrat MPs in the House of Commons, admitted that his party faces an "existential crisis" and adopting legalisation as party policy would boost the Lib Dems' bid to recover lost votes. "We have all committed to the fightback. If we are to succeed, if we are to stand for something, we have to articulate liberal values," said Lamb.