There is an area nearby completely overgrown with brambles, through which I
need to clear a simple pathway.

It would seem to me the ideal thing would be a thin bladed sword to slash
through it. But I don't have one (and I have never seen a similar thing in
garden tool shops). what would be an alternative method please? And would
someone recommend a specific tool, if there is one. ( I wouldn't want to buy
a mechanical 'strimmer' just for this rarely occuring job). Thanks.