Police are investigating a break-in at a self-storage facility in Hayes.
People's lock-ups were targeted in the burglary at Shurgard in Uxbridge Road.
One customer, who contacted getwestlondon and asked not to be named, said as many as 50 occupied units were raided. The Metropolitan Police confirmed that officers were called to the site in the early hours of this morning (Thursday), but were unable to say how many units had been affected at this stage.
A Shurgard spokesperson said: "Shurgard, one of the leading companies active in self-storage, is investigating a suspected break-in in its store in Hayes.
"Currently we do not have confirmation that anything was stolen and it appears to be an act of vandalism. Shurgard is currently collaborating with the police in order to identify what happened and we are offering support to the affected customers. As the investigation is ongoing, no information with regards to content or legal details can be disclosed.
"We always ask our customers as well to pay attention and be discrete. Unfortunately, despite all measures taken, crime can never be entirely excluded. We are working with the police in order to prevent future violations."
Security at the Hayes and Ruislip Shurgard sites came under scrutiny in December 2012, after both were raided within a week.
Following the Uxbridge Gazette report, BBC Watchdog investigators filmed undercover at the Ruislip branch, in Victoria Road, and claimed it was easy to get in, and remain in the building unchallenged.
Shurgard has 22 stores in London and the Thames Valley area. The Hayes site is open between 6am and 11pm, but unit holders can request 24-hour access.
On the Shurgard website, the company says its sites have a "strict combination of security management systems in place," with access controlled by a pin code, specially designed locks, and CCTV.
