By Adam Easton BBC News, Warsaw

Many Poles approve of the vetting - but there is much paperwork

A controversial law has come into force in Poland which requires up to 700,000 people to confess if they informed for the communist-era secret police.

Under the new rules, anyone who refuses to co-operate or lies about their past will be barred from working for a public company for 10 years.

The conservative government has made it a priority to purge ex-communists and their collaborators from public life.

For the first time, the secret police files will be opened to the public.

The new law greatly expands the number of people who will have to come clean about their pasts.

The archbishop of Warsaw resigned over his tainted past

Previously, only senior public servants were required to do so. Now academics, journalists, state company bosses and school headteachers will have to fill out a declaration or face dismissal.

Several senior journalists have threatened a boycott, saying the new law is reminiscent of communist times, when people were forced to sign loyalty pledges.

Those who admit to being informants will not be punished.

But one major problem is the current state of the communist secret police archives. Eighteen years after communism collapsed, they are now incomplete and some simply contain lies.

So people who deny collaboration in good faith may discover their secret police file says they were registered as an agent.