Public offered rare walks through Thames Tunnel

The Thames Tunnel runs from Rotherhithe to Wapping

Transport for London are offering rare walking tours through the London Overground Thames Tunnel this weekend, while trains are suspended for engineering work.

The £18 ticket cost will go to charity - but all 4,000 sold out in just 4 hours.

The tunnel was constructed in the 18th century, and it's only the second time in 150 years it has been open to the public.