Any ideas what this pipe is?

digging a hole for a red robin tree and found this iron (I think) pipe in the way. It’s at the end of our rear garden. Any ideas what it might be and level of risk if I decide to grind it out?

 

Its either water, gas or electic.......or it could part of an old bed

 

Looks like an old gas pipe

 

Leave it alone, its been there years , Gas /Water pipe

 

Roots will grow round it - if the hole's too shallow - cut a notch in the rootball. Get some michorhizal powder to help it start growing

 

Check your house plans? How was that pipe not found when the retaining wall was built?...surely the footings would have been deeper than that hole?
either way do as other people have said change the root ball and leave well alone..lol