And a Post Office expert reckons it was a chance in a million.
For while Elizabeth McMillan of Dryburgh Avenue was speaking to her sister-in-law Margaret in Philadelphia the phone call was interrupted by a third voice.
Amazingly, it was Margaret’s younger sister, Eileen, who lives in London.
Eileen had called her from a call box in Lincolnshire whilst on holiday but discovered, after putting her coins into the machine, that she was speaking to her sister who emigrated 11 years ago.
They spoke for a few minutes having a three-way conversation.
A PO spokesman said: ‘‘Double connections occur but this kind of thing is one in a million!’’