They will pay the same as they would for the regular landline call, and then in addition YOU pay for the cost of a call from your landline to your mobile (even though it's a divert and never touches your physical home phone)! *That's unless things have changed. The principle used to be that the person calling you would not be penalised, the extra costs fall on the line-owner, the same as if someone calls your mobile while you are abroad and you don't have international roaming.
