Tricky one( add dialling code in front of all numbers in list)

I am running a report with mobile numbers. and it gives me the numbers ( 7197757123) however i need to add dialling code 44 in front of these . as there are 20,000 of these i need a forumla to help.

so place 44 in A1 and the mobile number in b1, then i need a forumula for c1 to place a1 in front of b1

any help would be appreciated

thanks