LONDON (Reuters) Thousands of Britons marched through central London Saturday to celebrate the demise of the government's unpopular "poll tax" under the watchful of eyes of 5,000 police.

The estimated 11,000 demonstrators marched in a carnival atmosphere but police, some in riot gear, were out in force to prevent a repeat of an anti-poll tax riot last March which led to the worst violence in London in a decade.During that march, 600 people were injured, 400 arrested and thousands of dollars worth of damage caused.

Police said Saturday's march and rally in central Hyde Park were peaceful. Two arrests were made, one for theft and the other for being drunk and disorderly, and a female police officer was slightly injured.

Speakers at the rally hailed Prime Minister John Major's decision this week to scrap the hugely unpopular tax, which was imposed by his predecessor Margaret Thatcher and contributed to her downfall last November.

"You have proved that the Tories (the ruling Conservative Party) can be forced to back off and you should be proud of yourselves," opposition Labor Party member of parliament Dave Nellist said.

Thatcher introduced the tax - officially called the community charge - on all adults, saying it would be fairer than the property-based levy it replaced as the way of funding local government services from schools to refuse collection.

Major now plans to replace it with a new tax based on property values but taking into account the number of people living in each house.