Record-breaking British adventurer Sarah Outen will kayak under Tower Bridge at midday today to complete her gruelling four-and-a-half-year round the world expedition that has seen her cycle, kayak and row over 40,000 kilometres.

For the very last stretch of her London2London: Via the World expedition she will kayak up the Thames from Teddington to Tower Bridge – her starting point for the expedition back in April 2011.

During her expedition Sarah became the first person to row from Japan to Alaska but it is safe to say that this has not been an easy journey.

She survived a mid-Ocean rescue on the Pacific Ocean, cycled through brutal weather conditions in the Gobi Desert and kayaked some of the toughest waters in the world.

Sarah Outen arrives in Adak in theAleutian Islands on September 23, 2013.

Sarah’s journey started in April 2011 when she kayaked from London to France. From there she jumped on her bike and cycled a punishing 18,000km across Europe, Russia and Asia before kayaking to Japan. In 2012, she made her first attempt to row solo across the Pacific but this was cut short when she was hit by a tropical storm and had to be rescued.

She went back a year later and successfully rowed from Japan to Alaska in 150 days.

She then kayaked one of the toughest routes in the world – the 2.5km through the Aleutian Islands, off the coast of Alaska and is believed to be the first person to do this, before cycling across Alaska and North America to Cape Cod.

From here she set off to row solo across the Atlantic to the UK but was forced to call for a pick up due to hurricane Joaquin – she lost her boat Happy Socks during the evacuation from the ocean.

She then finished the expedition as planned by cycling and kayaking from Falmouth back up to London.