Google has categorically denied “conspiracy theories” accusing it of censoring its search results to please the Conservative party in exchange for an agreement to pay just £130m in back taxes.

The accusations stem from Google’s autocomplete function, which suggests search terms based on user input. The suggested searches are created algorithmically from previous searches on the topic.

Users who enter “Labour are” are offered completed terms including “… finished”, “… a joke”, and “… right wing”. Similarly, entering “Lib Dems are” offers up “… finished”, “… pointless” and “… traitors”. But entering “Conservatives are” or “Tories are” offers no search suggestions at all.

That prompted some to accuse Google of censoring its search terms to please the government. One Guardian reader, for instance, wrote to the paper to say that “in light of the recent tax scandal, it seems that the internet may be up for the right price”. Even the Daily Mail reported the conspiracy theories.

Just been told of this. Put "conservatives are" into Google. Notice - no autocomplete. Now try "labour are". Autocomplete is all negative. — Tom Phillips (@TomSprints) February 1, 2016

@alexhern Are google suppressing search results? Try 'Tories are' then 'Labour are' Coincidence? — Chris S-B (@_inkworm) February 2, 2016

A Google spokesperson told the Guardian that the company “can categorically state that tax is not remotely connected to this, nor are their ‘conspiracy theories’ founded in any way”.

Instead, Google said: “Autocomplete predictions are produced based on a number of factors including the popularity of search terms.”

So do searches for the Tories or Conservatives produce a different effect? Google offered a hint, saying: “We do remove offensive or inappropriate content from autocomplete predictions.” There’s even a web page where anyone can report offensive predictions.

It could be that the search results for “Tories are” and “Conservatives are” were so bad that the terms were removed automatically because they were so offensive. A similar override occurs for searches including “Christians are”, “Jews are”. Interestingly, “Muslims are” offers just one autocomplete: “Muslims are not terrorists”.

Or it could be the case that the Conservatives are better at reporting offensive terms than Labour or the Liberal Democrats – but a source close to the Conservative party told the Guardian it had not reported any offensive terms to Google.

Meanwhile, other searches for the same party do autocomplete: “The Conservative party is” completes with “your enemy”. A search for “Tory party is” offers another part of the puzzle, autocompleting to “Conservative party is bad” – suggesting that Google treats the two terms as interchangeable.