Idiom – Throw a spanner in the works

• Idiom – Throw a spanner in the works or Put a spanner in the works
• Meaning – To do something that prevents an activity or plan from happening or being successful. This expression is used when something or someone introduces a problem, obstacle or something unexpected. A spanner in the works will cause delays to the progress of something in some way. This problem may be a result of carelessness – or sabotage.
• In American English an adjustable spanner is called a monkey-wrench. As a result you might hear American people use the similar idiom – throw a monkey wrench in the works.
• To remember this phrase imagine what would happen if somebody threw a spanner into a moving engine or machine. The spanner would likely cause the gears or machine parts to smash or stop working in some way.
• In British English a spanner may also refer to a stupid or foolish person. “You forgot your wallet again? You are a complete spanner!” This usage is mildly offensive.

A set of spanners

Usage:

When could you use this idiom?

• When unexpected last-minute changes cause you problems.
• If somebody makes changes to a plan  – and puts the whole plan at risk.
• When somebody suddenly cannot make a prior engagement.
• A business unsuccessfully tries to release a new product.

Example:

• Bobby: “We were hoping to get married in January but now we can’t.”
• Mike: “Why not?”
• Bobby: “My future mother-in-law threw a spanner in the works! She’s going to Australia in January.”

Discuss: