PICTURED: More than 50 arrests at Hyde Park 420 Day Celebration pro-cannabis festival

Hyde Park became high park yesterday during the 420 Day Celebration that featured speeches in support of decriminalisation and smoking of the Class B drug in full view.

The thousands of people taking part were greeted by red police warning signs stating ‘Cannabis Is Illegal’ and that smokers risked landing themselves in trouble.

There were 53 arrests, all for drug-related offences, after uniformed officers stepped at Speaker's Corner.

Scotland Yard said 37 people were dealt with at Hyde Park police station, 10 were given a cannabis warning, six were handed a penalty notice, 21 were given police bail and 16 were taken in to custody.

Organiser Stewart Harper, of Norml-UK, said the event, one of 420 being held around the world, had been arranged because "we need legal access for cannabis and medical access to cannabis especially".

Of the people who are worried about the problems that drug use and addiction can trigger, Mr Harper said: "I can completely understand that - but if you regulated the market to make sure that substances were not sold to children and that it was regulated then that is a better situation, rather than leaving it without control and to anarchy in the black market.

"We prefer to look at this as a health issue rather than a criminal issue. We are thinking of how we can reduce the harm rather than saying this is illegal. Drugs is a real issue around the world. "

He called for a rethink of how the drug is treated in Britain and also pointed towards large scale problems of drugs smuggling and people who are killed or kidnapped internationally as reasons for changes to be made.