to lead someone on a wild goose chase
Wild goose chase see:-
http://www.phrases.org.uk/meanings/wild-goose-chase.html
A hopeless quest.
Origin
'This phrase is old and appears to be one of the many phrases introduced to the language by Shakespeare. The first recorded citation is from Romeo and Juliet, 1592:
Romeo: Switch and spurs, switch and spurs; or I'll cry a match.
Mercutio: Nay, if thy wits run the wild-goose chase, I have done, for thou hast more of the wild-goose in one of thy wits than, I am sure, I have in my whole five.
Our current use of the phrase alludes to an undertaking which will probably prove to be fruitless - and it's hard to imagine anything more doomed to failure than an attempt to catch a wild goose by chasing after it. Our understanding of the term differs from that in use in Shakespeare's day. The earlier meaning related not to hunting but to horse racing. A 'wild goose chase' was a chase in which horses followed a lead horse at a set distance, mimicking wild geese flying in formation. The equine connection was referred to in another early citation, just ten years after Shakespeare - Nicholas Breton's The Mother's Blessing, 1602:
"Esteeme a horse, according to his pace, But loose no wagers on a wilde goose chase."
That meaning had been lost by the 19th century. In Grose's Dictionary of the Vulgar Tongue, 1811, he defines the term much the way we do today:
"A tedious uncertain pursuit, like the following a flock of wild geese, who are remarkably shy."
The 1978 film 'The Wild Geese' alluded to the phrase in its title. This refers back to Irish mercenaries who 'flew' from Ireland to serve in various European armies in the 16th to 18th centuries. The plot of the film involved a group of mercenaries embarking on a near-impossible mission. Of course, the near-impossible is no problem for action heroes and they caught their prey. :down: