I found this picture of cars entering the tunnel but there is a queue of cars passing the booth on the left. The drivers must have had to lean over the passenger seat to pay the toll. Is this true? Or did they have a pre-paid pass similar to todays Fast Tag?

I got this picture off this website that contains many pictures I haven't seen before. They're mainly Rock Ferry but also has a few from Birkenhead and New Ferry Baths, which are hard to find.
Check them out here.
http://www.fredsalem.com/old-rock-ferry-photos/

Yes, there were tunnel contracts.

How would they know if someone had a contract?
You would still have to lean over the passenger seat to show it and the guy in the booth will be taking money from one side whilst keeping an eye on the cars on the other side. It is very arse about face, haha!

I imagine the bloke two cars behind in the middle queue was tasked with checking; if they didn't meet the credentials then he'd blow his whistle at them very hard indeed.

I used the new Runcorn bridge at the weekend, a far more sophisticated way of toll management. High time the tunnels adopted this principle.

You can pay for the tunnels by contactless now and of course the tag. Runcorn bridge assumes everybody has access to the internet which is simply not the case particularly the older generation. Even the new app for Mersey Gateway gets terrible feedback from users and people who try to use it.

I wonder if this should be in the history section somewhere?

https://www.roads.org.uk/sites/default/files/articles/queensway-tunnel/birkenhead.pdf

Nice find Moonstar, thanks

Great pictures, Moonstar. I noticed of the pictures of the congestion showed the traffic outside of the Empire Theatre. That is the same one I saw the Rolling Stones in concert a couple of years before. Memories!!.

Dingle,
Not the Empire, the Stones played the Majestic Ballroom further along.