Image caption Police taking bribes was highlighted as a major problem by the report

The world is a more corrupt place now than it was three years ago, a poll suggests.

Some 56% of people interviewed by Transparency International said their country had become more corrupt.

In Afghanistan, Nigeria, Iraq and India more than 50% of people said they had paid a bribe in the past year - many of them paying off the police.

Meanwhile, a BBC poll suggests that corruption is the world's most talked about problem.

About one in five of those polled for the BBC by GlobeScan said they had discussed issues relating to corruption with others in the last month, making it the most talked about concern ahead of climate change, poverty, unemployment and rising food and energy costs.

In the Transparency International survey, political parties were regarded as the most corrupt institutions with 80% of people regarding them as corrupt.

Political parties also topped the list in Transparency's 2004 barometer, with 71%.

Religious bodies experienced a sharp rise in people regarding them as corrupt - 28% in 2004 increased to 53% by 2010.

Some 50% of people believed their government was ineffective at tackling the problem of corruption.

'Worrying' trend

Transparency flagged up bribery as the major problem highlighted by the survey, with one in four of those polled saying they had paid a bribe in the past year.

Why pay a bribe? In sub-Saharan Africa, 67%of bribes were to avoid trouble with the authorities

In the Arab world and Latin America most bribes were paid to speed things up

In Asia-Pacific, 35% of people bribed to get a service they were entitled to

In North America and the EU, most bribe payers said they could not remember why they had paid Source: Global Corruption Barometer 2010 BBC World Service: Sweden and Somalia

Some 29% of bribes went to the police, 20% to registry and permit officials, and 14% to members of the judiciary.

Robin Hodess, Transparency's policy and research director, said police involvement in such transactions was "really worrying".

"It's a figure that's grown in the past few years. It's nearly doubled, in fact, since 2006. Nearly one in three people who had contact with the police around the world had to pay a bribe," she said.

While people from Cambodia (84%) and Liberia (89%) were the most likely to have to pay a bribe, the Danish respondents reported no bribery.

By region, people in sub-Saharan Africa were the most likely to have paid a bribe (56%).

Bribe-taking was least common in EU countries and North America (both 5%) - although these were the two regions seeing the biggest increase in concern about corruption.

Analysts blame this rising concern on the global financial crisis for undermining people's faith in government, banks and economic institutions.

The lobby group interviewed 90,000 people in 86 countries to compile its corruption barometer.

The opinion poll commissioned by the BBC sampled 13,000 people in 26 nations.

One question asked people to rate which issues they saw as most serious.

Corruption was ranked as the second most important topic behind poverty.

Respondents in Brazil, Egypt, Colombia, the Philippines and Kenya were especially likely to view corruption as a very serious issue.

In Europe, Italians were the most concerned about bribe-taking.

Publication of the BBC poll coincides with anti-corruption day held by the United Nations.