Throw a spanner in the works means disrupting or spoiling a plan. A spanner is a tool for nuts and bolts, and the works are the moving parts of a machine: throw the tool into the gears, and everything stops. It can be someone's fault or just bad luck: The road closure threw a spanner in the works. In the US, people say throw a wrench in the works.
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put / throw a spanner in the works; US throw a (monkey) wrench in the works
- The sudden road closure threw a spanner in the works for the delivery team.
- A missing signature could put a spanner in the works.
- The broken freezer threw a wrench in the works just before the food festival.
What changed
First versionThe cancelled train threw a spanner in the work.
RevisionThe cancelled train threw a spanner in the works.
Work usually means a job or effort, so the s seems unnecessary. But works here means machinery, the gears, and in that sense it always has an s. Add the s, and the tool lands in the machine again.
A bump in the road is a delay you get past. Throw a spanner in the works means something breaks the process, and the plan has to change. Sabotage is deliberate damage, while the spanner is often thrown by chance.
Your turn
Complete the British idiom: The missing key threw a spanner in the ___.
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works — Works here means machinery, and it always has an s. Work would just mean a job.
Describe something unexpected that ruined a trip, a party or a move. Use throw a spanner in the works.
The hall's broken heating threw a spanner in the works, so we moved the rehearsal.
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