Up to 130 sets of car keys have been stolen from a site used by a meet-and-greet company offering long-stay parking near Manchester Airport.
Four cars were also taken from the Car Park Manchester site in Hale, the Manchester Evening News reported.
Police said the full numbers involved were not yet known because many of the vehicles’ owners are still on holiday.
Car Park Manchester said it had reported the 18 August burglary but declined to comment further.
The company is not affiliated with Manchester Airport.
Cheryl Wilden said she discovered her sister’s car keys had been stolen after the pair returned from a holiday in Barcelona.
She said they had to retrieve a spare set of keys from Wakefield, West Yorkshire, before being taken to where the car had been left in a “muddy field”.
They then struggled to drive the brand new Hyundai out of the site because it was stuck in mud, Ms Wilden said.
“It was horrendous, there were lots of high value cars there. We were quite horrified,” she added.
“They eventually had to get the car out for us. It was not pleasant.
“I’m just absolutely devastated because I booked it.”
A spokesman for Manchester Airport said: “We would like to remind passengers that the airport offers a wide range of secure, official car parking facilities, and is also well connected via public transport.
“Anyone with any doubts about their car parking can verify it with our customer services team.”