A rowing squad of 30 hardy magistrates has been training hard as they prepare to take to the water for the Great River Race.

The oarsmen and women, who sit on the bench at Lavender Hill Magistrates' Court as well as courts in Richmond, Kingston and Wimbledon, are believed to be the only judicial crew taking part on Saturday, September 15.

They first came together in 2006 and this year escorted the Queen down the river in her jubilee pageant and also accompanied the Olympic torch.

Matt Preston from the Lavender Hill bench, who took up rowing to improve his fitness, convinced his colleagues to take part in the Great River Race six years ago.

He said: "Three colleagues enjoyed it so much they immediately agreed to buy a somewhat decrepit skiff we found that we could do up for use in future events.

"I don’t think any of us realised the fantastic journey we were embarking on. We have been rowing in the race ever since and our crews have included judges, magistrates, staff and friends from central and south-west London courts and to date we have raised nearly £50,000 for local charities."

Crowds will gather on the riverside to watch a fleet of more than 300 boats pass during the 21 mile race between London Docklands and Ham.

The magistrates, who will row in three vessels, made history when they were the first team from the judiciary to take part in 2006 - and now look set to become the largest.

Mr Preston added: "Our objectives are the same as the day we started - to increase understanding of our court work in a positive and light-hearted way, raising money for a selection of good causes and hopefully attract some of our colleagues into the pleasures of traditional rowing."

The team, aptly called the Bench Blisters, will raise money for Xpression, an activity club for teenagers with learning disabilities, Addaction Kaleidoscope, which gives addiction advice, and cancer charity MacMillan Cancer Support.

To sponsor the crew, visit uk.virginmoneygiving.com/team/GRR2012.