There was a short drama show with the (few) details I remember:
It featured a youth boy and an elderly woman.
The two got friendly, and so the woman trusted the young man.
This youth then stole some money from her home, and the woman then told someone of how she trusted him and "he turned out to be a rotten (rotter?)"
I also remember, but not sure, that the youth had a motorcycle and was repairing it on the street.
It was probably set in London (like a neighbourhood with council housing), and maybe shot around 1975 - 1978.
I found out something on memorabletv.com:
BANK HOLIDAY
BBC2 'Scene' / 1x30m-e / 1972
Writer: Colin Welland / Director: Ronald Smedley
Drama. Two hells angels go to the coast on bank holiday intent on causing trouble. Scene was actually a very long running Children's Schools TV anthology series that tried to feature dramas relevant to teenagers, occasionally high profile ones would get a repeat prime time showing.
With:- TONY TAYLOR / MYLES REITHERMAN / BILL DEAN
It might be part of this series, though not this particular episode
Any details are greatly appreciated.
Thanks.