The war on cannabis has been lost - it should be legalised, says Lord Hague

The war against cannabis has been "comprehensively and irreversibly lost", former Conservative leader William Hague has said, as he urges Theresa May to legalise the drug.

Writing in the  Telegraph Lord Hague says Mrs May should be "bold" and introduce a "major change" in policy, warning it is "deluded" to think cannabis can be "driven off the streets".

His intervention comes as the Prime Minister faces a growing Cabinet row over whether to allow medicinal use of the drug following pleas from the mother of 12 year-old Billy Caldwell. 

Two of her most senior ministers - Sajid Javid and Jeremy Hunt - are understood to be pushing for a review of cannabis use but the Prime Minister is said to have blocked the discussion at a Cabinet meeting yesterday.

But in his column, Lord Hague says the PM should go further and imitate Canada, which is on the verge of legalising the drug for recreational use, writing: " Can British Conservatives be as bold as Canadian Liberals? We ought to be."

Lord Hague led the Conservatives from 1997 to 2001 during which time he advocated a "zero tolerance" stance on the drug.

But today he says he has changed his mind on the issue and calls for Conservatives in Government to do the same. 

"The idea that this can be driven off the streets and out of people’s lives by the state is nothing short of deluded," he writes, adding: "Everyone sitting in a Whitehall conference room needs to recognise that, out there, cannabis is ubiquitous, and issuing orders to the police to defeat its use is about as up to date and relevant as asking the Army to recover the Empire. 

"This battle is effectively over."

Lord Hague warns only criminal gangs benefit from the drug being illegal and that many police forces have "stopped worrying about it", adding: "When a law has ceased to be credible and worth enforcing to many police as well as the public, respect for the law in general is damaged. 

"We should have laws we believe in and enforce or we should get rid of them."

The former Tory leader supported a zero-tolerance approach to cannabis during his time as leader but was undermined after it emerged seven of his own shadow cabinet had taken the drug themselves. 

The party has a complex history on the issue after David Cameron backed legalisation of medicinal cannabis in 2007 when he was leader but Mrs May consistently advocated a tough approach to law and order during her time as Home Secretary. 

Lord Hague's dramatic intervention comes as Mrs May faces a growing row within her Cabinet over whether the drug should be prescribed to children. 

It follows desperate pleas by the mother of 12 year-old Billy Caldwell after cannabis oil she brought into the UK from Canada for him was confiscated by the Home Office. It was later returned under emergency powers but a long-term solution is yet to be found.

Ministers announced on Monday that an expert panel will be set up to rule on individual cases following Billy's case, after he was admitted to hospital with severe seizures over the weekend.

Nick Hurd said the new panel, led by Dame Sally Davies, will give advice on whether cannabis should be allowed in specific cases, but the announced stopped short of a full review of the law demanded by Mr Javid and Mr Hunt.

Ministers are understood to have clashed over the issue earlier in the day when Mr Javid, the Home Secretary, repeatedly tried to raise the prospect of a full review during the morning's Cabinet meeting but was prevented by the Prime Minister. 

It came just an hour after Mr Hunt, the Health Secretary, told journalists a review of the law was already underway in an apparent bid to bounce Mrs May into agreeing to set one up.

Mr Javid is understood to have been pushing for collective agreement around the Cabinet table in order to announce a full review of the law, amid a growing public outcry over the issue. 

But Mrs May, who during her time as Home Secretary did not act on the issue, is understood to have significant concerns about whether there is enough evidence to relax restrictions on its use. 

MPs in the Commons expressed concern that some children would be forced to wait months for the Government to approve their use of the drug, while others including Dr Caroline Johnson warned not enough evidence exists to support its use. 

It came as Andy McDonald MP revealed his son Rory died aged 16 in 2006 after suffering an epileptic seizure. 

He has written to the Home Secretary calling for a blanket exemption on the use of cannabis oil to alleviate the illness and admitted he wonders if the drug could have saved his son.

British experts said there was now scientific consensus that medical cannabis could be useful in treating some forms of epilepsy.

Although the type of oil used by Billy Calder contains a small amount of the banned substance tetrahydrocannabinol (THC), most of it is cannabidiol (CBD) which is legal in Britain and which has as proved effective at preventing seizures in trials.

In April the Food and Drug Administration in the US granted approval for the first prescription cannabidiol medicine - Epidiolex - to treat rare and severe forms of epilepsy and the European Medicines Agency is also now considering licensing the drug.

Prof Celia Morgan, Professor of Psychopharmacology, University of Exeter, said: “We currently lag behind the rest of the world in our use and research of cannabinoid medicines.

“It seems a crucial time to introduce a more progressive legislation that means that children like Billy are able to access the most effective medicines for their conditions, determined by evidence, not legal status.”

However other experts warned that until evaluation was completed by the EMA it may risk patient safety to allow medical marijuana to be prescribed on a case-by-case basis.