Animal rights campaigners brought Oxford to a standstill as they staged their biggest protest march through the city.
About 1,000 people turned out on Saturday afternoon to protest against Oxford University continuing work on its partially-built �18m animal research laboratory in South Parks Road.
Brandishing placards, blowing whistles and sounding klaxons, the demonstrators demanded the attention of passing shoppers and tourists.
No arrests were made and no trouble reported.
But many traders in the city centre said the protest march had caused a huge downturn in trade.
Crowds of people lined the streets to witness the march as it progressed from Broad Street where a rally was held from 1pm through Turl Street to High Street.
In High Street, buses were forced to queue the length of the road while protesters marched towards Magdalen Bridge, The Plain and into Cowley Place.
From there, the protesters some dressed in blood-spattered lab coats, others carrying toy monkeys in cages returned across Magdalen Bridge, turning into Longwall Street, Holywell Street and Parks Road before ending the march in Keble Road, just a few hundred metres from the laboratory site.
From noon until about 2pm, the demonstrators gathered in Broad Street and the owner of a shop there, who did not want to be named, said her business had suffered as a result.
She said: "They made so much noise and created so much disruption that I think a lot of shoppers might have felt intimidated.
"Usually there are a lot of people browsing and just milling around on a Saturday, but not today. It's very quiet in here."
And as the protest passed through Holywell Street, the manager of the Holywell Bar and Restaurant, Chris Henderson, locked his doors He said: "This march has destroyed my business today. These people are not safe, I did not want to risk keeping the doors open while they passed by. My staff and I were afraid of what could happen."
Many protesters had travelled from as far afield as North Yorkshire, Ipswich and Somerset to take part.
Mick Rose, from North Yorkshire, was one of 50 people from the Leeds Animal Protection Group who travelled to Oxford.
He said: "We are here to demonstrate and show the university just how strongly we feel. We are here on behalf of the animals. We believe the laboratory will never be finished as a result of our protests."
Maria Langlois, a member of the Ipswich Animal Rights Group, added: "We want this demonstration to make people think about how animals suffer. We do not want to cause trouble, we just want the public to see why animal testing should be banned."
Mel Broughton, of the animal rights group Speak, led the march around the city.
Afterwards he said: "It has gone very well and been orderly and organised.
"This was all about showing the public how much support we have for our cause and we've done that effectively.
"But this is only a part of what has been more than a two-year long campaign, which we will continue to fight day after day."
Unlike the previous march in January at which five people were arrested, Saturday's protest passed peacefully.
A police spokesman said: "We are really pleased with the way it went. It was all peaceful and they were able to demonstrate without causing massive problems for the rest of Oxford."