A man was threatened at knifepoint as he sat in his car by a robber who smashed the window and escaped with his £4,000 Cartier watch.
Police said the victim, aged in his 50s, wasn't hurt in the robbery, but was left 'understandably shaken'.
Detectives in Prestwich have launched an investigation and are appealing for witnesses.
Police said the man was parked on the Clifton Road car park behind the NatWest bank off Bury New Road in Prestwich when the robber approached his car window.
He smashed the window then held the knife to his face, demanding his valuable watch.
The robbery happened at 10.50am on Tuesday, March 12, but details have only just been released by Greater Manchester Police.
A force spokesman said: "A man in his 50s was parked on Clifton Road car park, behind the Natwest bank in Prestwich, when a man approached his car window.
"The offender smashed the window before holding a knife to the man's face, demanding he hand over his watch.
"The offender then left in a black Nissan Micra with the watch - a black Cartier watch worth more than £4,000.
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"The man was uninjured but was left understandably shaken."
The robber has only been described as a man wearing a khaki-coloured tracksuit.
No further details have been revealed and the watch hasn't been described further.
GMP added: "Officers are appealing for information."
Call police on 0161 856 8172, quoting incident number 666 of 12/03/19, or contact Crimestoppers on 0800 555 111.
