Masked gang members have been filmed hurling packages of drugs over the walls of Britain's most troubled prisons.

The shocking footage was captured outside HMP Birmingham just days after inmates smashed up a wing and flooded cells at the facility.

The category B and C prison has had a huge problem with drug smuggling recently despite putting up protective nets to help combat the issue.   A source told the Star on Sunday that there were not enough police at the facility to stop the gangs.

The source said: 'The screws know it's coming over but there's nothing they can do.

'Spice, puff (cannabis), prescription pills like Subutex, booze, phones, food. Anything they want they can get. It comes over the back yard and cons go and pick it up. Simple as that. The footage consists of three videos, two of which were filmed during the day and one at night.

The gang members can be seen getting off their mopeds to chuck the contraband over the wall.

One of them can be heard shouting: 'Over the wall we go. Prison inspectors have said the prevalence of drugs at HMP Birmingham has contributed to an increase of violence within the facility.

In December last year, elite prison officers were called in to deal with a 12-hour riot which saw inmates rip their cells apart.

And last weekend prisoners left taps running before throwing furniture around the building.