The Electoral Commission (EC) has a statutory responsibility to promote awareness of elections, including registration. In this capacity, the EC leads public awareness campaigns on voter registration, notably ahead of elections.
The Government does not have an allocated budget for advertising voter registration deadlines
The exception was a government funded campaign in 2015 targeted specifically at overseas electors. The budget was £500k and new registrations increased by 570%, exceeding the target to receive 100k new applications from overseas electors before the registration deadline.
We do not hold any figures on local government spending on advertising to promote voter registration.