Sam Matthews of The Punting Company was angry. "It's provocative," he said. "It's somebody hoping to start a war to get rid of us. It's the competition, but which competition? I have my suspicions, but the best thing is not to retaliate."

Matthews is the latest victim of what locals call the "punt wars", a series of disputes between rival operators in the £2.5m punt industry in Cambridge. The battles have reached new heights after two of Matthews's boats were found sawn through from top to bottom.

The nighttime attack is the most audacious in the spate of clashes that have disrupted the tranquillity of the Cam and prompted calls for a cap on the number of boats competing for custom from the four million people who visit the city each year. Observers say punting is now in danger of becoming a tawdry industry that will lower the city's reputation.

The panoply of weapons used in the punting wars is said to include stink bombs thrown from bridges to render a rival's boat inoperable, washing up liquid squirted to make it too slippery for the punter to stand, and bolt-cutters to snap mooring chains. But never, until now, an electric jig saw.

"If it's happened to me," said Matthews, "who's next?"

Matthews, whose independent company jostles for space on the Cam with century-old established punting companies, more recent co-operatives, and "mobilers", so named because they have no established moorings, estimates damage to his boats in excess of £10,000.

Rod Ingersent, general manager of Scudamore's, the oldest and largest of the punting companies, described the attack as "a new departure".

"We've had argy bargy, touts fighting over tourists, pushing and shoving, yes. But everyone is a bit shocked because it is not something we have known before."

The growing number of punt operators employ touts who hunt in packs to talk tourists onto a chauffeured tour in huge 12-seater punt ferries at £14-a-head.

In the last three years, police have investigated 31 altercations between touts. One was said to have involved a knife, and in another a woman broke her hip when she was caught up in a brawl between touts.

James Bayliss-Smith, a freelance cameraman and part-time Cam punter who is making a documentary on the Punt Wars, believes there should be a cap on numbers. "Or better still, a ban on the over-sized 'ferry' punts. Unchecked, these behemoths have turned a serene and beautiful river into a log-jammed motorway," he said.

Cam Conservators, the body responsible for managing the river since 1710, grants licences to punt operators, but as long as the boats are properly constructed and a fee paid, they have no power to refuse a licence.

Two recent developments are said to have provoked the sawing of the two punts: the "battle of the Middle Steps" and Cambridge City Council's attempts to control the number of punt touts.

The Middle Steps leading down to the river are in between Scudamore's two pontoons at the Quayside punting station at Magdalene Bridge. Independent punt owners used to pick up and land tourists there, until it was declared unsafe by Cam Conservators. Blame was laid on the number of boats bumping into them and causing erosion.

"Rubbish" said one unnamed mobiler, who claims a member of Scudamore's staff was seen "pulling bricks out" to make the steps unsafe, so independents couldn't use them.

"Cobblers," Ingersent told the Guardian. "Somebody did fall in there. It was totally unsafe."

Banned from the steps, independents have this year found themselves also forbidden from landing on any council-owned land. Instead, the council set aside a special pontoon at Quayside, and granted a limited number of independents the right to trade from there.

The result, according to critics, has been chaos. Those unable to use Quayside or council greens have decamped to the only other spot they say they can legally land – a small concrete platform by a public bridge at Garret Hostel Lane.

The trouble is the Trinity Boys, an affiliation of punt owners named after the nearby college, have been trading there for 30 years. After a day's blockade, agreement was reached. The new boys – which includes Matthews – can pick up and land, but not tout from there. So, instead, they deploy their touts on nearby King's Parade and footfall along this central tourist haunt has yielded great riches.

Alastair Roberts, Cambridge City Council's safer communities officer, said the ban on punts using council land had been enforced because "the numbers were getting quite significant, with punts lined up all the way down the river bank". He added the new system had resulted in a drop in complaints from the public, he said.