Sportsmen set out in rainy weather to mark the first Boxing Day hunt since the new law came into effect earlier this year. The post-Christmas hunt is one of the most important traditions of Britain's rural areas, where opposition to the measures passed last year was strongest.
"Today (hunters) are showing their determination to keep hunting within the law until the Hunting Act is repealed or replaced," pro-hunting advocate Simon Hart said in a statement.
The Hunting Act, which took effect in February, outlaws traditional fox hunting and other kinds of sport in which dogs chase and kill prey. The legislation was passed after a caustic battle in Parliament and raucous demonstrations in the streets.
Hunt supporters have argued that fox hunting is vital to rural economies and a critical method of controlling predators. Detractors argue it is cruel and unnecessary.
Fox hunting, which dates back centuries in Britain, historically involved groups of riders following a pack of hounds trained to track down and kill foxes.
Under the new law, small packs of two dogs can legally be used to locate a fox and flush it out into open ground, but not to harm the animal. The prey is instead shot by one of the sportsmen.
Most of the tens of thousands of spectators who gathered Monday at around 250 meetings across Britain watched trail or drag hunting, in which the only point is for dogs to track an animal's scent, which has been artificially laid out through the woods in advance. No animals are harmed in such a hunt.
Would-be hunters can still get dressed up, blow their horns, gallop about and then head to the pub, but it's not the same thing, reports CBS News' Larry Miller.
"We like the tradition and we want it to stay," said one huntsman.
Animal rights campaigners claim many people turned up at events Monday because they believed no harm would come to any animals, League Against Cruel Sports spokesman Mike Hobday said.
"There's a whole group of people in the countryside who don't believe in cruelty, who don't believe it is right to chase foxes and who are free for the first time to get involved with hunts," he said. "We don't believe there is any mood amongst the public to think that chasing and abusing animals for entertainment is acceptable for a modern society."
Hobday's group has identified a catalogue of misdemeanors since Nov. 5, when the latest hunting season began.
At one of the bigger hunts, some 4,000 supporters turned up in the southwestern county of Gloucestershire, to see riders and their hounds set off into the woods and take part in the prestigious Beaufort Hunt. Past participants in the event have included Prince Charles and his sons, William and Harry.
"Support is up, definitely," the Beaufort Hunt's secretary Nigel Maidment said. "There's certainly a very resilient feeling — people want to see an end to this stupid act. More people than ever are prepared to give us their support."