That tunnel was more likely to be part of the drain system or other service duct for tranmere tunnels. There is substantial water ingress as you mentioned previously as well as toilets to cater for 6000 people. If that tunnel was not full of water it shows it probably is a drain.

Thanks for the info, something to watch out for

I suppose that's a possible answer but improbable as my uncle lived in that house way before those tunnels were built and the drainage system was installed. I think it would be likely he would have known had they dug a drainage tunnel through his back yard and under his house.

I have been all round the basement, sub basement and adjoining service tunnels and I have not seen any.

I would also like to take this opportunity to dispel the Arrowe park secret car park under maternity rumour which is also untrue. Apart from a handful of plant rooms and 2 switch rooms the only other place the public and general staff don't see under maternity is a reasonably big storage area that just contains two big water tanks,old light fittings, a couple of old floor buffers, a pool table and a few other bits.

I too can confirm what kevin is saying regarding the basement below the maternity block. Entrance which is adjacent to the staircase. Pleny of old bedside reading lights which they still use for spares !!

There used to be all sorts down there but they had a clear out at some point. We used to regularly go down there to rob bits off the old nurse call panels to repair other ones still in use and also to pinch the old style fire alarm interfaces. We treated it like a bone yard.
You can look through the air bricks and spy on the people walking around outside the front haha. Also occasionally you can hear women screaming in labour in the delivery room above.

Sorry. Totally off topic.