Not quite!

Q: You're approaching a bridge that has no height restriction on it. What's the minimum height under the bridge?
Correct answer:
5 metres (16 feet 6 inches)
Explanation
The headroom under bridges in the UK is at least 5 metres (16 feet 6 inches), unless otherwise stated. Where the overhead clearance is arched, this headroom is normally only between the limits marked.
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