Saturday's (April 20) Oxford City Bumping Races are expected to be the biggest in recent history with more than 200 rowers competing.

City of Oxford Rowing Club, front, and Imperial College, London, back

Hundreds of spectators are expected to line Donnington Bridge and the towpath along the Isis to watch 36 crews compete for the Head of the River title.

In the men's division, a crew from Imperial College, London, is defending its title for the third year running and is being chased by Merton College and City of Oxford Rowing Club (CORC), among others.

In the women's division, CORC is defending the title, chased by Merton College, Wolfson College and other crews, including two teams from neighbouring Falcon Rowing and Canoe Club.

The historic races were originally established back in 1889 and were held annually until 1968.

After a long gap, City of Oxford Rowing Club revived the tradition in 2000 to mark the new Millennium and encourage non-university clubs to take up bumps racing.

Race chairman Paul Azzopardi said: "We have doubled the number of entrants and it promises to be an exciting day.

"We revived it and the numbers have doubled in the last year, which is great.

"We do have a problem recruiting non-college clubs to take part because some perceive bumping as dangerous. But it's great fun. To have 36 crews this year is fantastic."

Winning crews collect medals and have their names engraved on the Head of the River Trophy, which dates back to 1889.

Sixteen races will take place during the day from 10am to 5.30pm, every half hour.

Crews of four rowers and a cox will be lined up along the river, about 80ft apart. The aim is to catch up with the boat in front and bump into it. The boat in front then drops out of the race and the crew that bumped it wins the right to start further along the river in the next round.