Solar-powered civil servant sails the Thames

Mike Manisty, 59, chief information officer for the National Offender Management Service, was due to pass through Marlow today after setting off from Westminster last week.

His supporters include Alex Allan, chairman of the Joint Intelligence Committee, and Prison Service head Phil Wheatley, who were among the 150-strong crowd who saw him off with a chorus of Rule Britannia.

Mr Manisty's boat Corvelia is an adapted 12ft Thames launch.

He estimates his journey to the river's navigable source in Lechlade will take two to three weeks. He hopes to travel nine miles a day, passing through his home town of Windsor, as well as Reading and Oxford, sleeping on board.

The father-of-four, who is soon to retire, is raising money for the charity Action for Prisoners' Families. He also wants to highlight eco-friendly boating as a future form of transport.

He told the Evening Standard: "The gin-palace set have been a bit snooty but people on barges have been very nice, making me lots of cups of tea and donating money to the charity."

"This is such a small boat but it is quite stable, so there aren't too many problems with wash from big barges. Other river users are very tolerant of little craft, you just have to keep alert."

Mr Manisty took a month to adapt the boat with solar panels using skills from his Navy training. The panels feed a battery, which powers the motor, a laptop, radio, satnav and small fridge for a well-earned gin and tonic.