A retired research scientist from Cambridge is refusing to pay his television licence fee in protest at the BBC's uncritical coverage of the European Union. "We are moving towards an oppressive super-state yet the BBC gives us very little real information about it," he says. "It reminds me of Soviet propaganda. It really does."

On the face of it, the comparison sounds a little excessive. But this particular licence refusenik, Vladimir Bukovsky, has actually spent 12 years of his life in Soviet psychiatric hospitals and prison camps. As a civil rights campaigner, he did more than anyone else to expose the persecution of dissidents during the Brezhnev era.

Earlier this month, Bukovsky stood outside the reception of Broadcasting House and took a pair of scissors to a giant facsimile of his licence. Needless to say, there were no BBC television cameras present to record the event but it will have acutely embarrassed the corporation at a time when the Eurosceptic campaign against BBC bias is gathering pace.

For the past year or two, sarcastic paragraphs have been appearing in diary columns, offering miniature illustrations of the corporation's Europhile mindset - reporting, for example, that production staff were seen applauding pro-federalist speakers during a televised debate on the EU or that Martha Kearney, Newsnight's political editor, had agreed to judge an essay competition entitled: "Why are we afraid of the European Union?"

Minotaur, an independent monitoring unit run by a former head of publicity for BBC News, is currently analysing every reference to Europe on the Today programme. Previous Minotaur surveys have covered the 2001 general election and the launch of the euro notes and coins.

Each has come to the same conclusion: that the corporation's European coverage is slanted in favour of the single currency and presents the case for withdrawal from the EU as, in the words of one BBC correspondent, "flat-earth politics".

So far, the BBC has found it easy to shrug off the Minotaur reports. It points out that they have been commissioned by the arch-Eurosceptic Lord Pearson of Rannoch and are therefore not quite as independent as they might seem.

There are signs, however, that corporation executives are more worried than they are prepared to admit. Anne Sloman, the corporation's political adviser, has been spotted lunching with Pearson. The meeting was cordial but it is hard to imagine anyone less likely to win over the corporation's critics.

According to a BBC current affairs presenter who understandably refuses to be named, she once told him: "Don't you realise that these people [hard-line opponents of the EU] are mad?"

Pearson's organisation, Global Britain, has posted several hundred pages of Minotaur findings on its website,  http://www.telegraph.co.uk/news/exit.jhtml?exit=http://www.globalbritain.org. Although in places the reports do seem one-sided, reading too much into slips of the tongue or hurried editorial decisions, taken as a whole they point to a subliminal BBC "line" on Europe that is difficult to reconcile with the obligation of impartiality set down in its charter.

In the five years up to 2002, Eurosceptics became increasingly convinced that the BBC was acting as an unofficial cheerleader for the single currency. Several programmes employed the device of inviting pro and anti-euro lobbyists to change the minds of a target audience but, on closer inspection, seemed designed to produce a particular outcome.

A 1997 Panorama studio debate achieved an 18 per cent swing to the euro in less than an hour. In 2001, Referendum Street subjected residents of a north London street to the arguments of both sides.

But, not long before filming began, the Eurosceptic Zac Goldsmith withdrew from the project because of the producers' insistence that their anti-euro team should be led by the unappealing David Mellor.

This time, the swing was 23 per cent in two days, though viewers were given no evidence about how the polls were conducted. When Panorama repeated its debate this May, there was another swing to the euro but only after 40 voting machines were switched off "to refine the sample".

By this stage, many Eurosceptics were convinced that the BBC would try to nudge the electorate in a referendum, just as it has admitted doing in the 1975 Common Market vote, when Today disseminated pro-EEC information supplied by the Foreign Office.

Public opposition to the euro fell during 2001; Minotaur speculated that the BBC's positive coverage "could well have contributed to this significant change".

The high-water mark of euro-enthusiasm was reached this January when the euro notes and coins were launched. "Euphoria in Euroland," was the opening line on the Ten O'Clock News. "Euphoria at the BBC" might have been a better description.

This was how Paul Mason of Newsnight reported the scenes in Maastricht: "As the midnight hour approached, a giant inflatable euro tree blossomed into life. For once, the Ode to Joy seemed exactly the right tune."

Jim Naughtie, in Paris for Today, struck an almost Biblical note: "The arrival of the currency that the fathers of modern Europe dreamed about are [sic] all symbols made flesh."

As it turned out, it was the last good news about the EU the BBC could report for nearly a year, until the agreement on enlargement. The value of the euro dropped as the Germany economy went into seizure; allegations of corruption were levelled against the European Commission by Marta Andreasen, its sacked chief accountant. Blair argued with Chirac.

Some BBC programmes reported these developments impartially. Others seemed intent on acting as a buffer between the bad news from Europe and the public.

The Six O'Clock News, after reporting Andreasen's charges, went over to a BBC correspondent in Brussels who simply repeated the EU's rubbishing of Andreasen; the Commission's press officer couldn't have done better.

The latest Minotaur report focuses on Today's handling of the last European Council summit. The Franco-German deal to cap farm subsidies caught the programme by surprise, says Minotaur, and its review of the press on Oct 25 played down its significance. Listeners were told that the agreement was opposed by "those European conspiracy theorists" the Sun and the Daily Mail.

The next day, it emerged that Tony Blair had made a scathing attack on the deal. On Oct 29, his stand-up row with Chirac dominated the newspaper headlines.

Today reported it briefly but a crucial part of the story, the cancellation of an Anglo-French summit, was ignored until Oct 30 when, bizarrely, the Rev Leslie Griffiths announced it on Thought for the Day with the comment: "What a to-do!" Throughout all this, only two out of 13 interviewees expressed negative sentiments about Brussels.

The case for withdrawal from the EU was not heard. But then, as Minotaur says, it almost never is. Thirty per cent of the electorate want to leave the EU but you would never guess that from the BBC's output, which treats the pro-withdrawal lobby as an eccentric or malevolent force.

A television news report during the election showed a UKIP candidate hammering at a campaign board. He was shot from a low angle, the sky throwing his face into shadow: pure Hitchcock.

"Steve Reed wants to smash the European Union to pieces," said the commentary. Why is there such antipathy to anti-EU campaigners? According to one senior BBC journalist, it is because their opinions fall outside "the fairly thin band of ideology that gets the stamp of approval".

In August, the BBC accepted a £25 million EU loan to make programmes, tying its commercial future into the success of the EU project. For the BBC's Labour-supporting chairman and director-general, support for the EU makes ideological and commercial sense.

Yet there is no evidence that the management dictates a pro-euro line to its senior journalists, most of whom would scream blue murder if it tried to.

But, in a sense it does not have to because, outside a small circle of independent-minded correspondents, there is a vast army of junior reporters, script editors and researchers whose right-on prejudices - on Europe, hunting, immigration and abortion - are so instinctive that they are not even aware of them. This is hardly surprising, given that they are recruited mainly though the media pages of the Guardian.

If, over the next few years, the strain of enlargement begins to pull Europe apart, it will be interesting to see if the BBC will allow a national debate over Britain's membership - or, to put it another way, whether million of licence payers who oppose membership will get their money's worth.

At the moment, the signals are mixed. Richard Sambrook, head of news, has warned his journalists that they need to be more concerned about impartiality. On the other hand, no public institution is quite so resistant to criticism as the BBC.

A few months ago Andrew Turner, the Tory MP, wrote to Gayvn Davies, the BBC chairman, asking about the Minotaur reports - documents that contain the most detailed allegations of bias ever levelled against the corporation. Davies's reply was positively Olympian in its condescension.

"BBC management have not so far alerted us [the Governors] through the normal reporting channels of any issues raised by the Minotaur reports of bias in our coverage," he wrote. "I therefore have no reason to believe that these reports give grounds for concern."