The survey also looked at some of the strange objects left behind in cabs around the world, they include:
- A wig and a bird in a cage left behind in a US cab
- A prosthetic leg and an ex-boyfriend left in an Australian taxi
- A trombone in Finland
- Dentures in Germany
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Paramedics were on standby outside the police cordon as armed officers stood by the property.
A team of researchers has taken samples from the ten busiest London Underground lines to work out which are the dirtiest.
The action comes on top of an emergency timetable which has seen hundreds of trains a day being axed.