TAVISTOCK police reported a spate of strange 'phone calls to residents in the area this week.
PC Sid Siddall said they had been getting seven or eight calls a day from people who had answered the 'phone only to find the line silent.
He said this was probably due to 'block dialling' by direct marketing organisations — a process where several numbers are dialled at a time, but only the first one to answer gets to talk to the sales person.
PC Siddall said there had also been a rash of complaints about 'hard-sell' recently.
He said if people wanted to avoid the attentions of these companies they could register for an opt-out list.
All direct marketing organisations have to consult the list and risk breaking the law if they call those included.
Call 0845 0700 707 to prevent all unsolicited calls to both telephones and faxes. It takes 28 days for inclusion to take effect.
'Hopefully, that will save us some unnecessary work,' said PC Siddall.