The Government today hailed an EU agreement to introduce a blanket ban on dumping dead fish back in the sea.
Fisheries minister Richard Benyon called it "a historic moment".
"The scandal of discards has gone on for too long and I'm delighted that the UK has taken such a central role in securing this agreement," Benyon said after marathon talks in Brussels.
Earlier this month MEPs overwhelmingly backed the biggest-ever Common Fisheries Policy reforms, crucially including an end to so-called "discards".
In the UK, TV chef Hugh Fearnley-Whittingstall launched a "Discards Campaign" that has so far attracted more than 850,000 signatures on a petition.
The EU Fisheries Commissioner said almost one quarter of all fish caught in European waters is being dumped at sea due to discards.
Mackerel is no longer a sustainable choice for a fish supper and should be eaten only occasionally, conservationists have warned amid overfishing of the stock.
The Marine Conservation Society said it had removed mackerel, an oily fish packed with omega 3, from its latest "fish to eat" list.
Atlantic populations of mackerel have moved north-west into Icelandic and Faroe Islands waters, prompting their fishermen to fish more stock.
"The total catch is now far in excess of what has been scientifically recommended and previously agreed upon by all participating countries," said Bernadette Clarke of the Marine Conservation Society.
The conservation group said good alternatives to mackerel were herring and sardine.
"We're in the internationals area, I have the right to fish," shouted one French fisherman.
"We preserve the resources, we let [the scallops] reproduce and grow during the summer and it's the others who came and get the benefit of our work," said Pascal Marie, another French fisherman.
A spokeswoman for the Maritime and Coastguard Agency said:
It was reported to us on Monday that a number of British fishing vessels were being confronted by French fishing vessels off the coast of Le Havre.
As this is outside UK waters, we contacted the French coastguard, who sent a French patrol vessel to the area.
We continue to liaise with the French authorities who have been dealing with the situation.
Rod Henderson, head of coastal operations for the the Marine Management Organisation, said:
As soon as the MMO was made aware of the situation, our officers contacted the French authorities and encouraged them to intervene. They did and are continuing to deal with this matter.
It is the responsibility of the French authorities to ensure the safety of UK vessels in their waters. Had the situation occurred in UK waters, the Royal Navy would have responded.
Royal Navy fisheries protection vessels do sometimes cross the median line into French waters where a joint operation has been pre-agreed. The next joint operation is already scheduled, and the Royal Navy may soon have a presence in the area as part of this patrol.
The MMO is continuing high-level discussions with French counterparts to seek assurances that these issues will not recur.
The MMO is also liaising with the Maritime and Coastguard Agency, which has responsibility for collision at sea regulations, to resolve this issue.
British boats are entitled to fish in the area, 20 miles north west of Le Havre, even though it is in French waters.
The area had recently been closed off to French vessels by local authorities but was reopened on October 1, the spokeswoman said. UK boats were still entitled to enter the waters during the "closure" period.
The MMO spokeswoman said one reason the closure could have been put in place was so scallop stock levels could be replenished.
The situation was eventually defused after the MMO contacted the French authorities, who intervened.
French fishermen have reportedly been pelting British boats with rocks and flares in a row over scallop fishing in the English Channel, the Marine Management Organisation (MMO) said today.
British fishermen reported the attacks to the MMO, which said an estimated 40 French vessels and eight UK vessels were involved in Monday's incident in scalloping grounds in the Bay de Seine.
A spokeswoman could not confirm whether the French fishermen were throwing rocks and flares, but said they had received reports from one of the UK vessels that this was the case.