Telecoms giants have been urged to scrap charges for calling the 101 police non-emergency number as the Home Office promised a review of the 15p cost.
Vodafone said it would end charges for its pay-as-you-go users, because they "tend to be more vulnerable".
Home Secretary Sajid Javid's department urged other mobile providers to follow Vodafone's lead.
A Home Office spokesman said: "We welcome Vodafone's decision and would encourage other mobile phone operators to follow their lead, whilst we review charges for the 101 non-emergency telephone number."
The Daily Telegraph reported that Vodafone will make 101 calls free for all seven million of its pay-as-you-go users from the end of this month, exempting them from the 15p flat-rate fee.
A spokesman for the firm said: "We have been looking to make improvements for customers.
"It was decided it would be beneficial for pay-as-you-go customers who tend to be more vulnerable to zero-rate the 101 service."
In a report last month, outgoing Victims Commissioner Baroness Newlove recommended reviewing the cost of 101 calls to see whether they should be free, like dialling 999.
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