In message , Nigel M
writes
Some men just came to trim a tree below an overhead power cable. They
had what looked like an electric carving knife, a one handed chainsaw.

so was it like a chainsaw or like a carving knife?

Assuming the latter some sort of reciprocating saw. It was probably
something like a Dewalt alligator saw or Bosch Tyrannosaw -these have
two opposing blades that move against each other - cutting better in
heavier duty materials than a single bladed reciprocating saw.

http://www.tooled-up.com/MicroCategory.asp?CID=4&SCID=20&MCID=585

For examples (not necessarily cheapest, just the first good link I
found)
--
Chris French and Helen Johnson, Leeds
urg Suppliers and References FAQ:
http://www.familyfrench.co.uk/garden/urgfaq/index.html