That is a minor oversight that will probably be rectified at some point — other countries are doing it, it is already required in Northern Ireland, and in 2018 a pilot will be held introducing the requirement in a number of districts¹.

People likely won't resist it too much. We've had this identification requirement imposed upon us in the Netherlands a few years ago, and while there is valid criticism on this requirement, it passed. So to vote now you need to bring a valid ID. If the British government wants to do this with a minimum of fuss, they'll do what our government did and make the driver's licence a valid identity card. That way the majority of adults will already have their ID on them as a matter of habit (and won't complain).

Of course mentioning that it is needed to prevent Muslim voters from committing voting fraud (see¹…) will help push the bill trough.

1: http://www.telegraph.co.uk/news/2016/12/27/voters-will-have-...