A GANG of heartless con men who preyed on old and vulnerable victims were caught by police after grabbing a brooch, a court heard on Monday.o

Posing as council workmen, investigating a tower block water contamination, two men entered the flat of a couple in their 80s, snatching the brooch and fleeing.

Irishman Jim Dunn, 37, of Chingford Road, Walthamstow, and jobless Michael McCarthy, 19, of Clive Road, Enfield, pleaded guilty to burgling the couple in Chaucer Court, Howard Road, Stoke Newington, on July 13 2001.

Police, suspecting they were responsible for a string of similar crimes, launched a covert surveillance operation and arrested the pair nearby along with Michael McCarthy senior, 41, also of Clive Road. He pleaded guilty to dishonestly handling the stolen brooch on the same day.

Southwark Crown Court judge Peter Fingret told Dunn and McCarthy junior: "This was a particularly mean and terrifying offence.

"To have two strangers come into one's property in these circumstances is an appalling situation, particularly when the occupants there are in their 80s and one is housebound.

''It was carefully planned and executed but your behaviour was fortunately observed by police officers. You both gained the confidence of the householder and her housebound husband.''

Alcoholic drug addict Dunn was on the run from prison after he was jailed for raiding the home of a hospital patient pensioner with McCarthy junior and previously burgled an old lady while posing as a water company official.

Father-of-four Dunn, who remained at large for five months, was jailed for three years. McCarthy junior, who tried to kill himself while on remand, was given 18 months youth custody, and father-of-six scrap dealer McCarthy senior the head of an Irish travelling family was ordered to complete 80-hours community service.

Prosecutor Louis Mably told the court: ''Dunn and McCarthy junior conned their way into the home of an 81-year-old lady and stole a brooch that had great sentimental value to her and her 83-year-old husband.''

Police tailed the trio as they cruised housing estates and residential streets in a white transit van.

They regularly swapped clothing to confuse the evidence and drove erratically as an anti-surveillance device.

McCarthy senior sat in the van while his son rang Edna Harrison's eighth fIoor doorbell claiming he was concerned with pigeons contaminating the water system, insisting he needed to test water from the block's tank.

He left her door open behind him as he fiddled underneath the sink allowing Dunn to enter and rummage around the bedroom, where he was confronted by the couple.

They found him in the bedroom and he put his ear to the wall and began tapping,'' added Mr Mably.

''Terrified though the elderly couple were, they asked them to leave the house.''

McCarthy junior insisted a T-shirt motif was his official ID.

Police stopped the getaway van nearby and the brooch was found stashed inside the roof lining above McCarthy senior's head. It was later returned to the couple.

Even in their cell they tried to foil police by flushing clothing down the toilet along with the soles of their trainers. Clothing was also hidden in the bedding.