In what may be the biggest protest against Uber, more than 30,000 cab and limo drivers across Europe are reportedly staging demonstrations against the on-demand car service, stating that the company's arrival will threaten their livelihood.

Traffic came to a standstill in London on Wednesday as black cabbies staged a widespread strike against the Uber taxi-hailing app. (Casey Capachi/The Washington Post)

 

The protests have caused traffic jams and standstills in London. Here's a look.

Right before the protests from London's black cabs, Uber introduces UberTaxi:

 

London police are going cab to cab:

 

Outside Parliament:

 

The Strand:

 

Trafalgar Square:

 

Congestion in Whitehall:

 

A view from above:

 

Reports filter in about the cabdrivers' protests backfiring: