01/03/2011 02:53 PM
The firm confirmed it is reviewing its security procedures after the incident in the early hours of Monday morning, in which its Basingstoke exchange centre was broken into.
Criminals struck between 01:00GMT and 02:00GMT, damaging equipment and stealing specialist network and IT hardware.
"Several hundred thousand" people are thought to have been affected, mainly in the M4 corridor area, the company said.
Vodafone said its customers' private data had not been compromised, however.
"All our sites are protected by high level security systems - we're reviewing these with the police in the light of last night's break in," the firm said.
Hampshire Police said its detectives are investigating the burglary, which it said appeared to be a targeted attack.
Vodafone made the UK's first mobile call at a few minutes past midnight on 1 January 1985.