Two teenage con artists have been pocketing charity cash in a deceitful swimathon scam, residents have claimed.

The boys, aged around 14, knocked at houses in Gravel Hill, Addington claiming to be collecting donations for Shirley High School.

Some residents handed over cash immediately while others signed up to sponsor the boys as much as £20 to take part in the National Schools Swimathon, believing the money would go to Marie Curie Cancer Care.

But after one local became suspicious and investigated, it emerged that the school was not even taking part in the event - and had never heard of the boys.

Now residents are urging neighbours to be vigilant to avoid falling prey to the ruse.

Tony Munnery, 63, who sponsored the boys £5, said: "They seemed quite enthusiastic and had leaflets to hand out and everything. I never thought anything more of it until I heard the school had no knowledge of them.

"It is not a nice thing to do. They were going up and down the road. They are scamming a lot of people."

Another Gravel Hill resident, who asked not to be named, said: "They have been cunning. There are lots of older people around here who are very likely to sponsor them.

She added: "If they do not get stopped now they will just get more devious and put more plans together."

PC Ricky Phillips, of New Addington Safer Neighbourhoods team, said: "If people believe there is a scam then they should get in touch with us. If we are made aware of it then we will investigate it."