This is the moment a police officer was caught pepper spraying a serial robber as he dangled from a tower block drainpipe 100 feet from the ground.

PC Luke Wenham, 31, blasted Carl Cumberbatch twice as he tried to escape at Albert Barnes House in Elephant and Castle, London.

Cumberbatch momentarily lost his footing and was temporarily blinded, clinging to the drainpipe with one hand.

PC Wenham's career is now in ruins after he was convicted of two counts of common assault at Westminster magistrates' court today.

The officer sobbed as District Judge Louisa Ciecióra told him there was an 'obvious risk' of Cumberbatch falling to his death.

Meanwhile Cumberbatch was later convicted of 11 charges of robbery, two of criminal damage and two counts of racially aggravated public order. 

The footage released by the Independent Office for Police Conduct (IOPC) shows PC Wenham using the spray twice as Cumberbatch, wanted for several robberies, clambered down the side of the building.

When police arrived at the 12th floor flat Cumberbatch barricaded his door with furniture and officers had to force entry on August 17 last year.

Cumberbatch then dashed to the window and scrambled down the drainpipe.

'It was between the 12th and 10th floors that PC Wenham sprayed Mr Cumberbatch with irritant spray from the window of flat 73,' said Tom Broomfield, prosecuting.

'A member of the public filmed what was happening.

It clearly shows PC Wenham calling Mr Cumberbatch's name... while he is on the side of the building holding on to the pipe.

'In response Mr Cumberbatch looked up to where PC Wenham was calling from and then PC Wenham deployed the spray in the direction of Mr Cumberbatch whilst Mr Cumberbatch had hold of the pipe with only one hand.

'That appeared to result in Mr Cumberbatch momentarily losing his footing.