UKH

I have a delightful and seemingly unkillable sycamore sapling that's decided to grow in exactly the wrong place: from behind the service running up into my external gas meter box from the ground at the front of my house. Obviously I don't want it to get any bigger because the service is the inevitable loser in this particular fight.

Any tips on murdering the little bastard?

Glyphosate

OR probably more environmentally friendly salt and boiling water

Glyphosphate it is. I'm *trying* to kill this particular bit of environment.

bet you woood have a different view it it was a MonkeyPuzzle tree ?

chop it off and then give the stump a good cooking with a blowtorch singeing the bark a good couple of inches down around the stump and dry out the top inch.  Takes a few minutes. If it is really determined cook down to the roots.

Hmm, blowtorch,  gas main. I am seeing a tiny flaw in this plan....

You're right but it will solve the problem one way or other...

What worked for a small tree stump in my last place was to saw it down then drill a good sized (25mm at least) hole in the stump, fill the hole with Jeyes fluid and tape some polythene over it. No re-growth in 2 years plus. 

Making a hole in the stump and pouring something unpleasant like oil, or Glyphosate and covering it would mimic the little plugs which are sometimes put into stumps to stop them from re-growing. 

SBK stump killer is a much better bet than glyphosate. Cut it back but leave about 200mm, drill down into the centre then fill up with SBK & seal up the top (we’ve got clay soil so I use that). 

Leave the tree there and relocate your house.

Easier than all those - drill a hole and push some copper wire into it so that the copper crosses from the outside air, through the bark and into the wood.  Good tight fit, so cable rather than flex.

I've always wondered what they were...